computervocabularytranslation23feb08 1 spam pyrf; 2 wysbygi 0wfpfbd*sd 3 firewall zkd

8/14/2019 ComputerVocabularyTranslation23feb08 1 Spam Pyrf; 2 WYSBYGI 0wfpfbD*sD 3 Firewall Zkd

http://slidepdf.com/reader/full/computervocabularytranslation23feb08-1-spam-pyrf-2-wysbygi-0wfpfbdsd-3-firewall 1/367

omputerVocabularyTranslation23feb08

spam pyrf;

WYSBYGI 0wfpfbD*sD

firewall zkd if; &m; a0gvf

packet yufuuf

communications protocol qufoG,fa&; y&dkwdkaum

a TCP/IPTransmission Control Protocol/Internet Protocol Data ydk.&mwGifxdef;cs kyfaomy&dkwdkaum^tifwmeufy&dkwdkaum

SMPT (Simple Mail Transfer Protocol) &dk;&Sif;aomar;vfx&efpzm; y&dkwdkaum

snail mail yufusdar;vf

throughput o&l;yGwf

black box bl;euf

0 outsourcing atmufqdk.qif;^jyify

zGJ.tpnf;rsm;eJ.yl;aygif;aqmif&Gufjcif;^jyify üo,HZmw&SmazGjcif;/

1 click uvpfvkyfjcif;

2 double-click (2)Mudrfuvpfvkyfjcif;3 run time &rf;rfwdkif;rf

4 run-time error &rf;rfwdkif;rftrSm;



5 ADSL(asymmetric digital subscriber line) at'Dtufpft,fvf

6 POP(Post Office Protocol ) pmwdkuf y&dkwdkaum

7a volatile memory rwnfjrJaomrif;rdk&D

7b nonvolatile memory wnfjrJaomrif;rdk&D

7c flash memory zvufcsf rif;rdk&D

8 IP (Internet Protocol ) tifwmeufy&dkwkdaum

9 benign virus tjypfuif;aomAdkif;,yfpf

19 benign virus (n) tjypfuif;aomAdkif;,yfpf

if;,yfpf\*kPfowÅdudkyifaz:jyaomy&dk*&rfjzpfonf/y&dk*&rfudkxyfwvJvJ

;jcif;ponf.tjypf&dSaomfvnf; computer systemsMuD;pGmaomtEå&m,fudkrjzpfapaom Adkif;,yfpfjzpfonf/

Friday , November 23, 2007

oHk;rsm; aom tifwmeufESif.uGefjy lwma0g[m&rsm;bmomjyef/

e.urÇmMuD;wGifuRef awmfwdk.onfuGefjy lwma0g[m&rsm;ESif.eyef;owfae



ayjyD/ uGefjy lwma0g[m&rsm;wae.wjcm; arG;zGm; vm ae&m enf;ynm

ay:wdk;wufrKSwdk.udkdkem;v,foabmayguf&efteJqHk;vdktyfcsufrSmtajcc.

usqHk;jzpfonf.a0g[m&rsm;\taMumif;aoaojcmjcma&a&&m&modbdk.vdktyfw,f/

ynm&Sifr[kwfaomolrsm;twGufa&;om;jcif;jzpfygonf/

1spam(n) (vb) pyrf;

awmiff;cH rSm,ljcif;r&dSbJydk.aomtDar;vfpmrsm;/

ajrmufrsm;vSaomolrsm;xHHwpfjyd kifeuff xJ ay;y.dkaom

owif;tcsuftvufrsm;?aqmif;yg;rsm;/

y.dk vdkufaom owif;tcsuftvufrsm;?aqmif;yg;rsm;onfvufcH&&dSaomoleJ.r oufqdkifaomt&mrsm;jzpfaewwfonf/Oyrm

vltcGif.ta&;umuG,fapmif.a&Smufjcif;ESif.ywfoufaomowif;



tcsuftvufrsm;udk vuf,mtpGef;a&muf^vljz

ltpGef;a&muftzGJ.tpnf;rsm;

(ku klus kan)/ vljzltpGef;a&muftzGJ.tpnf;rsm;ponfwdk.odk.odk.ay;ydk.jcif;/

xdkuJ.odk.rrSmMum;bJay;ojzif.vufcH&&dSolrsm;\ar;vfabmufpf

rsm; wGiftrdS kufozG,fjzpfaewwfonf/

(spam) onf ae.pOfoHk;EHS k ;aoma0g[m& (Junk mail) ESif.qifwlaomtDvufxa&mepfpum;vHk;

jzpfygonf/

2 WYSBYGI(adj)( What You See Before You Get

It ) 0wfpfbD*sD

rdrd \a&;om;aom ( documents ) rsm;\ zGef . (font) t&G,f?umvmponf wdk.udkSk Mud kwifMunf.&S k jy kjyifEdS kifaom?aomjrifuGif;/

3firewall(n ) zkd if; &m; a0gvf tifwmeufpaomjyifyuGef,ufwckckrSjcdrf;ajcmufrKS



krsm;udkumuG,f&efwnfaqmufxm;aom vHkjcH

ka&;tzGJ.tpnf;jzpfonf/[wf0Jaqm.0J(2)ckvHk;yg0ifonf/

zkd if; &m; a0gvf (firewall) onff tzGJ.tpnf;wck\

uGefjy lwmrsm;udk

jyifyuGef,ufESif.wdkuf&dkufqufoG,fír&&efjzwfawmufwm;jrpf xm;onf/

qufoG,frS ktm;vHk;udk ya&mfqDqm.Am;(proxy server)

rSwqif.

jy kvkyf&onf/

ya&mfqDqm.Am; onfwpHkwckaomowif;

tcsuftvuf\vHkjcH krS k&dSr&dSudkqHk;jzwfay;onf/

4packet(n) yufuuf

uGef,ufwckwGifu&d,mwckrStjcm;u&d,mwckodk.

owif;tcsuftvufrsm; ay;ydk.jcif;^

vufcHjcif;jy kvkyf&mwGiftoHk;jy

kaomowif;tcsuftvufrsm;\,lepf/

yufuufwck udk owif;tcsuftvuf (data) rsm;?acgif;pOf



(header) rsm;? ay;ydk.aomu&d,m\vdyfp m vufcHrnf.u&d,m\vdyfpm? trSm;xdef;

owif;tcsuftvufrsm ; ( error-control data ) rsm;jzif.zGJ.pnf;xm;ygonf/

5communications protocol(n) qufoG,fa&; y&dkwdkaum

uGefjy lwmwckESif.wckcsdwfquf&efESif.owif;tcsuftvufrsm ;

zvS,f&mwGifvdkufem&aom pHowf rSwfcsufrsm;( standards) ESif.

pnf;rsOf;rsm; ( A set of rules )/ þ y&dkwdkaumrsm;udkvdkufemygutrSm;teJqHk;jzif.vG,fulacsmarG.pGmquf

oG,f Edkifrnf/

trsm;vufcHaomy&dkwdkaumwGifaqmzf0J [wf0JJ vf(7)vTm pkjzif.zGJ.pnf;

xm;ygonf/

5aTCP/IP

Transmission Control Protocol/Internet Protocol

Data ydk.&mwGifxdef;cs kyfaomy&dkwdkaum^tifwmeufy&dkwdkaum

rsd k;rwlaomuGef,ufrsm;qufoG,f&mwGiftoHk;jy kaomy&dkwdkaumtpk/



Department of Defense for communications rSpwiftoHk;jy konf/tifwmeuftygt0ifuGef,ufrsm;rSwqif. data

ydk.&mwGiftrsm;vufcHtoHk;jy kaom standard y&dkwdkaumjzpfvmonf/

6(SMTP)Simple Mail Transfer Protocol (n)

&dk;&Sif;aomar;vfx&efpzm; y&dkwdkaum

þ y&dkwdkaumudk tifwmeufwGiftD;ar;vfrsm;ydk.&mwGiftoHk;

jy kygonf/

7snail mail yufusdar;vf tifwmeufay:wGifor&kd;us ^&kd;&dk;pmwdkuf rSydk.aomar;vf0efaqmifrS kudk&nf

nTef;ajymqdkaompum;&yfjzpfonf/

tD;ar;vfESif.EdS kif;,SOfvQifor&kd;us ^&kd;&dk;pmwdkuf

rSydk.aomar;vf0efaqmifrS konftvGefaES;auG;onfudk&nf nTef;ajymqdkaompum;&yfjzpfonf/&dk;&dk;ar;vfudkysuf&,fjy kaom

"derogatory phrase" pum;&yfjzpfonf/

8throughput(n) o&l;yGwf

1 uGef,ufwck\owif;tcsuftvufjzef.csDaomtjrefES kef;?



wpuú HhwGifjzef.csDaom bit ta&twGuf (bits per second

bps) ESif.wdk if ;wmonf/bit qdkonf rSm owif;tcsuftvuf\,lepf

jzpfonf/binary digit \twdkaumufudk qdk vdkonf/

okn (0) odk.r[kwf wpf (1) udkqdk vdkonf/

2 uGefjy lwmtzGJ.tpnf;wck \^rS owif; tcsuft

vufjy kjyifaomtjrefES kef ;udkwdkif;wmaom,lepfjzpffonf/

(measure of data processing rate).

9black box

9black box bl;euf

[wf0Jvf(odk.r[kwf)aqm.zf0Jvf\,lepfwpfck? bl;euftwGif;

tao;pdwfzGJ.pnf;yHkudkod7efrvdkbJ tvkyfvkyf aqmifyHk function

udkod,HkrQjzif. designer onfol. design wGifxnf.oGif;toHk;

jy kEdkifygw,f/Oyrm tm;jzif. memory chip udk

bl;eufwpfcktjzpf,lqjyD;uGefjy lwmudk design jy kvkyfEdkifygw,ff/



memory chip designers onf omvQif chip

twGif;tao;pdwfzGJ.pnf;yHk tvkyfvkyf aqmifyHk function udkem;v,foabmayguf&efwmf0ef,l&ygw,f/

10outsourcing atmufqdk.qif;^ jyifytzGJ.tpnf;rsm;eJ.yl;aygif; aqmif&Gufjcif;^jyify üo,HZmw&SmazGjcif;

oDjcm;uefx&d kufwmrsm; twdkifyifcHyk8dkvfrsm; 0ef

aqmifrS ay;aom jA l&dkrsm;udkoD;jcm;wm0efcGJ a0owfrSwfay;jcif;/

data entry, programming ponf.vkyfief;rsm;udk

atmufqdk.qif;rSwq if.jy kvkyfav.&dSw,f/

11click(v) uvpfvkyfjcif;

mouse cvkyfudkae&mra&T.bJatmufudkEdSyfjyD;vTwfvdkufjcif;?

item wckudk a&G;cs,f&ef (odk.r[kwf) program wckudk

activate vkyf&ef uvpfvkyf&onf/



12double-click(v) (2)Mudrfuvpfvkyfjcif;

mouse cvkyfudkae&mra&T.bJatmufudk

(2)MudrfEdSyfjyD;vTwfvdkufjcif;? program wckudkdkjrefjref a&G;cs,f&ef ESif.activate vkyf&ef double-clicking udkvkyf&onf/

my love20jan2008

13run time &rf;wdkif;rf

y&dk&rfwckjyD;ajrmufatmif run vkyf&efMumaomtcsdef/

14run-time error &rf;rfwdkif;rftrSm;

y&dk&rfwck run vkyf&mwGifcompiler rSawG.&dSaomaqm.zf0JtrSm;/

15ADSL Asymmetric Digital Subscriber Line

at'Dtufpft,fvf

Asymmetric Digital Subscriber Line

twGuftwdkcs kyfjzpfonf/ video signals rsm;tygt0ifES kef;jref'pf*spfw,fqufoG,fa&;udkomref&dk;&dk;w,fvDzkef;Mud k;jzif.aqmif&Gufed kifaom u&d,mESif.enf;ynm/



at'Dtufpft,fvfudktoHk;jy kjyD; 8 Mbps (megabits per

second) xd customer rSowif;SvufcHEdkifjyD; 640

Kbps (kilobits per second) xd customer uowif;ydk.Edkifygonf/bit qdkonf rSm owif;tcsuftvuf\,lepf



vQyfppfu&d,mrsm;wGifAdk.tm;&dSjcif;udk(1)? Adk.tm;r&dSjcif;udk(0)ponfjzif.az:jy&efvG,fultqifajyrS k&dSojzif.

okn (0) ESif. wpf (1)bdkife&D(2)udktajccHaom udef;*Pef;pepf (binary number system) udktDvufx&GefepfqufoG,fa&;wGiftoHk;jy kMuonf/

vlwGifvuf(10)acsmif;&dSojzif.(10)udktajccHaom udef;*Pef;pepf (decimal number system)udkae.pOfa&wGuf&mwGifoHk;Muonf/

ADSLpepfudkoHk;jcif;tm;jzif.tifwmeufESif.csdwfquf&mwGif&dk;&dk;w ,fvDzkef;jzif.qufoG,fjcif;xufvQifjrefaomES kef;udk&&dSed

kifygonf/



6 POP Post Office Protocol pmwdkuf y&dkwdkaum

tifwmeufay:wGiftD;ar;vfrsm;vufcHjcif;?odkavSmifodrf;qnf;x

m;jcif;? ydk.jcif;jy kvkyf&mwGif servers rsm;rStoHk;jy kaom y&dkwdkaum/ servers rsm;ESif.csdwfqufxm;aomclient

computers rsm;uvnf;tD;ar;vfrsm;upload/download

vkyf&ef pop y&dkwdkaumudkyiftoHk;jy konf/


vQyfppfyg0gjywfawmufoGm;aomtcgaysmufqHk;oGm;wwfonf.R AM(random access memory) uJ.odk. rwnfjrJaomrif;rdk&D/

17b nonvolatile memory wnfjrJaomrif;rdk& D


Qyfppfyg0gjywfawmufoGm;aomfvnf; data

m;aysmufqkH;jcif;r&dSonf.data odkavSmifaomtzGJ.tpnf;/ core

memory, ROM, EPROM, flash memory, bubble memory,r battery-backed CMOS RAM ponf. rif;rdk&D wdk h&nfnTef;ajymqdkygonf/




vkyfaqmif&Guf&mwGif EEPROM memory ESif.qifwlaom

nonvolatile memory) wnfjrJaomrif;rdk&D jzpfon f/EEPROMmemory udkzsuf&mwGif

yte wckcsif;zsufed kifaomfvnf; flash memory zvufcsf rif;rdk&D udk

ock vdkufomzsuf ed kifonf/ flash memory udk portable

omputers rsm;wGif hard disks

tm;jznf.&ef(odk.r[kwf)tpm;xdk;&eftoHk;jy kav.&dSonf/

ash memory udk PC Card tjzpf&&dS ed kifjyD;PCMCIA slotifxdk;pdkufjyD;oHk;ed kifonf/

8 IP (Internet Protocol) tifwmeufy&dkwkdaum

ata messages rsm;udk packets rsm;tjzpfajymif;vJzGJ.pnf;jcif;?

if; packets rsm;udk sender r Sdestination network and station

ufqdkif&mvrf;aMumif;toD;oD;odk.wifay;jcif;(routing)?

estination a&mufaomtcg packets rsm;udkrlv data messages

m;tjzpfjyefvnfajymif;vJzGJ.pnf;jcif; (reassembly of packets into

he original data messages at the destination) onf.vkyfief;rsm;aqmif&Gufay;onf.TCP/IP y&dkwkdaum\tpdwftydkif;/



pare spare spare

1spam(n) (vb) pyrf;

awmiff;cH

rSm,ljcif;r&dSbJydk.aomtDar;vfpmrsm;/



y.dk vdkufaom owif;tcsuftvufrsm;?aqmif;yg;rsm;onfvufcH&&dSaomoleJ.rouf qdkifaomt&mrsm;jzpfaewwfonf/Oyrm vltcGif.ta&;umuG,fapmif.a&Smufjcif;ESif.ywfoufaomowif;tcsuf

tvufrsm;udk vuf,mtpGef;a&muf̂ vljz ltpGef;a&muftzGJ.tpnf;rsm;

(ku klus kan)/ vljzltpGef;a&muftzGJ.tpnf;rsm;ponfwdk.odk.odk.ay;ydk.jcif;/

xdkuJ.odk.rrSmMum;bJay;ojzif.vufcH&&dSolrsm;\ar;vfabmufpfrsm;

wGiftrdS kufozG,fjzpfaewwfonf/


jzpfygonf/

2 WYSBYGI(adj) 0wfpfbD*sD



What You See Before You Get It

rdrd \a&;om;aom ( documents ) rsm;\ zGef. (font)

t&G,f?umvmponf wdk.udkSk Mud kwifMunf.&S k jy kjyifEdS kifaom?aomjrifuGif;/

3firewall

3firewall(n) zkd if; &m; a0gvf tifwmeufpaomjyifyuGef,ufwckckrSjcdrf;ajcmufrKS

krsm;udkumuG,f&efwnfaqmufxm;aom vHkjcH ka&;tzGJ.tpnf;jzpfonf/[wf0Jaqm.0J(2)ckvHk;yg0ifonf/


uGefjy lwmrsm;udk

jyifyuGef,ufESif.wdkuf&dkufqufoG,fír&&efjzwfawmufwm;jrpfxm;o

nf/

qufoG,frS ktm;vHk;udk ya&mfqDqm.Am; (proxy server) rSwqif.

jy kvkyf&onf/





4packet

4packet(n) yufuuf

uGef,ufwckwGifu&d,mwckrStjcm;u&d,mwckodk. owif;tcsuftvufrsm; ay;ydk.jcif;^

vufcHjcif;jy kvkyf&mwGiftoHk;jy kaomowif;tcsuftvufrsm;\,lepf/


(header) rsm;? ay;ydk.aomu&d,m\vdyfpm vufcHrnf.u&d,m\vdyfpm? trSm;xdef; owif;tcsuftvufrsm; (

error-control data ) rsm;jzif.zGJ.pnf;xm;ygonf/


uGefjy lwmwckESif.wckcsdwfquf&efESif.owif;tcsuftvufrsm;



oG,f Edkifrnf/

trsm;vufcHaomy&dkwdkaumwGifaqmzf0J [wf0J(7)vTm pkjzif.zGJ.pnf;

xm;ygonf/







9black box

9black box bl;euf












aqmifrS kay;aom jA l&dkrsm;udkoD;jcm;wm0efcGJ a0owfrSwfay;jcif;/



my love

11click


mouse cvkyfudkae&mra&T.bJatmufudkEdSyfjyD;vTwfvdkufjcif;? item

wckudk a&G;cs,f&ef (odk.r[kwf) program wckudk activate vkyf&ef uvpfvkyf&onf/


mouse cvkyfudkae&mra&T.bJatmufudk (2)MudrfEdSyfjyD;vTwfvdkufjcif;?

program wckudkdkjrefjref a&G;cs,f&ef ESif.activate vkyf&ef double-clicking udkvkyf&onf/

outsourcing atmufqdk.qif;^ jyifytzGJ.tpnf;rsm;eJ.yl;aygif;



aqmif&Gufjcif;^jyify üo,HZmw&SmazGjcif;

oDjcm;uefx&d kufwmrsm; twdkifyifcHyk8dkvfrsm; 0ef aqmifrS kay;aom jA l&dkrsm;udkoD;jcm;wm0efcGJ a0owfrSwfay;jcif;/



9 benign virus (n) tjypfuif;aomAdkif;,yfpf if;,yfpf\*kPfowÅdudkyifaz:jyaomy&dk*&rfjzpfonf/y&dk*&rfudkxyfwvJvJ

;jcif;ponf.tjypf&dSaomfvnf; computer systemsMuD;pGmaomtEå&m,fudkrjzpfapaom Adkif;,yfpfjzpfonf/

spare spare

omputerVocabularyTranslation$

spam pyrf;

WYSBYGI 0wfpfbD*sD

firewall zkd if; &m; a0gvf

packet yufuuf communications protocol qufoG,fa&; y&dkwdkaum

a TCP/IPTransmission Control Protocol/Internet Protocol Data ydk.&mwGifxdef;cs kyfaomy&dkwdkaum^tifwmeufy&dkwdkaum



SMPT (Simple Mail Transfer Protocol) &dk;&Sif;aomar;vfx&efpzm;

y&dkwdkaum

snail mail yufusdar;vf

throughput o&l;yGwf

black box bl;euf

0 outsourcing atmufqdk.qif;^jyify

zGJ.tpnf;rsm;eJ.yl;aygif;aqmif&Gufjcif;^jyify üo,HZmw&SmazGjcif;/

1 click uvpfvkyfjcif;

2 double-click (2)Mudrfuvpfvkyfjcif;

3 run time &rf;rfwdkif;rf

4 run-time error &rf;rfwdkif;rftrSm;

15 ADSL(asymmetric digital subscriber line) at'Dtufpft,fvf

6 POP(Post Office Protocol ) pmwdkuf y&dkwdkaum






8 IP (Internet Protocol ) tifwmeufy&dkwkdaum

Friday , November 23, 2007

oHk;rsm; aom tifwmeufESif.uGefjy lwma0g[m&rsm;bmomjyef/

e.urÇmMuD;wGifuRef awmfwdk.onfuGefjy lwma0g[m&rsm;ESif.eyef;owfae

ayjyD/ uGefjy lwma0g[m&rsm;wae.wjcm; arG;zGm; vm ae&m enf;ynm

ay:wdk;wufrSwdk.udkdkem;v,foabmayguf&efteJqHk;vdktyfcsufrSmtajcc

usqHk;jzpfonf.a0g[m&rsm;\taMumif;aoaojcmjcma&a&&m&modbdk.vdktyfw,f/

ynm&Sifr[kwfaomolrsm;twGufa&;om;jcif;jzpfygonf/

1spam(n) (vb) pyrf; awmiff;cH rSm,ljcif;r&dSbJydk.aomtDar;vfpmrsm;/





y.dk vdkufaom

owif;tcsuftvufrsm;?aqmif;yg;rsm;onfvufcH&&dSaomoleJ.r oufqdkifaomt&mrsm;jzpfaewwfonf/Oyrm

vltcGif.ta&;umuG,fapmif.a&Smufjcif;ESif.ywfoufaomowif; tcsuftvufrsm;udk vuf,mtpGef;a&muf^vljz ltpGef;a&muftzGJ.tpnf;rsm;

(ku klus kan)/

vljzltpGef;a&muftzGJ.tpnf;rsm;ponfwdk.odk.odk.ay;ydk.jcif;/

xdkuJ.odk.rrSmMum;bJay;ojzif.vufcH&&dSolrsm;\ar;vfabmufpf

rsm; wGiftrdS kufozG,fjzpfaewwfonf/

(spam) onf ae.pOfoHk;EHS k ;aoma0g[m& (Junk mail)

ESif.qifwlaomtDvufxa&mepfpum;vHk;

jzpfygonf/

2 WYSBYGI(adj)( What You See Before You GetIt )

0wfpfbD*sD rdrd \a&;om;aom ( documents ) rsm;\ zGef . (font) t&G,f?umvmponf wdk.udkSk Mud kwifMunf.&S k jy kjyifEdS kifaom?aomjrifuGif;/



3firewall(n ) zkd if; &m; a0gvf

tifwmeufpaomjyifyuGef,ufwckckrSjcdrf;ajcmufrKS

krsm;udkumuG,f&efwnfaqmufxm;aom vHkjcH ka&;tzGJ.tpnf;jzpfonf/[wf0Jaqm.0J(2)ckvHk;yg0ifonf/


uGefjy lwmrsm;udk

jyifyuGef,ufESif.wdkuf&dkufqufoG,fír&&efjzwfawmufwm;jrpf

xm;onf/

qufoG,frS ktm;vHk;udk ya&mfqDqm.Am;(proxy server) rSwqif.

jy kvkyf&onf/



4packet(n) yufuuf






(header) rsm;? ay;ydk.aomu&d,m\vdyfp m vufcHrnf.u&d,m\vdyfpm? trSm;xdef;

owif;tcsuftvufrsm ; ( error-control data ) rsm;jzif.zGJ.pnf;xm;ygonf/


uGefjy lwmwckESif.wckcsdwfquf&efESif.owif;tcsuftvufrsm ;



oG,f Edkifrnf/

trsm;vufcHaomy&dkwdkaumwGifaqmzf0J [wf0JJ vf(7)vTm pkjzif.zGJ.pnf;

xm;ygonf/

5aTCP/IP

Transmission Control Protocol/Internet Protocol

Data ydk.&mwGifxdef;cs kyfaomy&dkwdkaum^tifwmeufy&dkwdkaum



rsd k;rwlaomuGef,ufrsm;qufoG,f&mwGiftoHk;jy kaomy&dkwdkaumtpk/

Department of Defense for communications

rSpwiftoHk;jy konf/tifwmeuftygt0ifuGef,ufrsm;rSwqif. data

ydk.&mwGiftrsm;vufcHtoHk;jy kaom standard y&dkwdkaumjzpfvmonf/

6(SMTP)Simple Mail Transfer Protocol (n)



jy kygonf/

7snail mail yufusdar;vf tifwmeufay:wGifor&kd;us ^&kd;&dk;pmwdkuf rSydk.aomar;vf0efaqmifrS kudk&nf nTef;ajymqdkaompum;&yfjzpfonf/

tD;ar;vfESif.EdS kif;,SOfvQifor&kd;us ^&kd;&dk;pmwdkuf rSydk.aomar;vf0efaqmifrS konftvGefaES;auG;onfudk&nf

nTef;ajymqdkaompum;&yfjzpfonf/&dk;&dk;ar;vfudkysuf&,fjy kaom













9black box

9black box bl;euf












aqmifrS ay;aom jA l&dkrsm;udkoD;jcm;wm0efcGJ a0owfrSwfay;jcif;/




mouse cvkyfudkae&mra&T.bJatmufudkEdSyfjyD;vTwfvdkufjcif;?

item wckudk a&G;cs,f&ef (odk.r[kwf) program wckudk

activate vkyf&ef uvpfvkyf&onf/




mouse cvkyfudkae&mra&T.bJatmufudk

(2)MudrfEdSyfjyD;vTwfvdkufjcif;? program wckudkdkjrefjref a&G;cs,f&ef ESif.activate vkyf&ef double-clicking udkvkyf&onf/

my love20jan2008

13run time &rf;wdkif;rf

y&dk&rfwckjyD;ajrmufatmif run vkyf&efMumaomtcsdef/

14run-time error &rf;rfwdkif;rftrSm;

y&dk&rfwck run vkyf&mwGifcompiler rSawG.&dSaomaqm.zf0JtrSm;/

15ADSL Asymmetric Digital Subscriber Line

at'Dtufpft,fvf

Asymmetric Digital Subscriber Line

twGuftwdkcs kyfjzpfonf/ video signals rsm;tygt0ifES kef;jref'pf*spfw,fqufoG,fa&;udkomref&dk;&dk;w,fvDzkef;Mud k;jzif.aqmif&Gufed kifaom u&d,mESif.enf;ynm/



6 POP Post Office Protocol pmwdkuf y&dkwdkaum

tifwmeufay:wGiftD;ar;vfrsm;vufcHjcif;?odkavSmifodrf;qnf;x

m;jcif;? ydk.jcif;jy kvkyf&mwGif servers rsm;rStoHk;jy kaom y&dkwdkaum/ servers rsm;ESif.csdwfqufxm;aomclient

computers rsm;uvnf;tD;ar;vfrsm;upload/download

vkyf&ef pop y&dkwdkaumudkyiftoHk;jy konf/


vQyfppfyg0gjywfawmufoGm;aomtcgaysmufqHk;oGm;wwfonf.R AM(random access memory) uJ.odk. rwnfjrJaomrif;rdk&D/

17b nonvolatile memory wnfjrJaomrif;rdk& D


Qyfppfyg0gjywfawmufoGm;aomfvnf; data

m;aysmufqkH;jcif;r&dSonf.data odkavSmifaomtzGJ.tpnf;/ core

memory, ROM, EPROM, flash memory, bubble memory,r battery-backed CMOS RAM ponf. rif;rdk&D wdk h&nfnTef;ajymqdkygonf/




vkyfaqmif&Guf&mwGif EEPROM memory ESif.qifwlaom

nonvolatile memory) wnfjrJaomrif;rdk&D jzpfon f/EEPROMmemory udkzsuf&mwGif

yte wckcsif;zsufed kifaomfvnf; flash memory zvufcsf rif;rdk&D udk

ock vdkufomzsuf ed kifonf/ flash memory udk portable

omputers rsm;wGif hard disks

tm;jznf.&ef(odk.r[kwf)tpm;xdk;&eftoHk;jy kav.&dSonf/

ash memory udk PC Card tjzpf&&dS ed kifjyD;PCMCIA slotifxdk;pdkufjyD;oHk;ed kifonf/

8 IP (Internet Protocol) tifwmeufy&dkwkdaum

ata messages rsm;udk packets rsm;tjzpfajymif;vJzGJ.pnf;jcif;?

if; packets rsm;udk sender r Sdestination network and station

ufqdkif&mvrf;aMumif;toD;oD;odk.wifay;jcif;(routing)?

estination a&mufaomtcg packets rsm;udkrlv data messages

m;tjzpfjyefvnfajymif;vJzGJ.pnf;jcif; (reassembly of packets into

he original data messages at the destination) onf.vkyfief;rsm;aqmif&Gufay;onf.TCP/IP y&dkwkdaum\tpdwftydkif;/



To continue

*pproammable interrupt controller

n. An Intel chip that handles interrupt requests

(IRQs). IBM AT machines use twoprogrammable interrupt controllers toaccommodate a maximum of 15 IRQs. Theprogrammable interrupt controller has beenreplaced by the advanced programmableinterrupt controller (APIC), which supportsmultiprocessing. Acronym: PIC. See also IBM

AT, IRQ.

circuit switching

n. A method of opening communications lines,

as through the telephone system, by creating aphysical link between the initiating and receivingparties. In circuit switching, the connection ismade at a switching center, which physicallyconnects the two parties and maintains an open



line between them for as long as needed. Circuitswitching is typically used on the dial-uptelephone network, and it is also used on a

smaller scale in privately maintainedcommunications networks. Unlike other methodsof transmission, such as packet switching, itrequires the link to be established before anycommunication can take place. Comparemessage switching, packet switching

WYSIWYG

markup language

n. A set of codes in a text file that instruct a

computer how to format it on a printer or videodisplay or how to index and link its contents.Examples of markup languages are HypertextMarkup Language (HTML) and ExtensibleMarkup Language (XML), which are used in Webpages, and Standard Generalized MarkupLanguage (SGML), which is used for typesettingand desktop publishing purposes and inelectronic documents. Markup languages of thissort are designed to enable documents andother files to be platform-independent and



highly portable between applications. See alsoHTML, SGML, XML.

interfacen. 1. The point at which a connection is madebetween two elements so that they can work with each other or exchange information. 2.Software that enables a program to work withthe user (the user interface, which can be a

command-line interface, menu-driven, or agraphical user interface), with another programsuch as the operating system, or with thecomputer's hardware. See also applicationprogramming interface, graphical user interface.3. A card, plug, or other device that connects

pieces of hardware with the computer so thatinformation can be moved from place to place.For example, standardized interfaces such asRS-232-C standard and SCSI enablecommunications between computers andprinters or disks. See also RS-232-C standard,SCSI.

.pdf

n. The file extension that identifies documentsencoded in the Portable Document Format



n. An object-oriented version of the Cprogramming language, developed by BjarneStroustrup in the early 1980s at Bell

Laboratories and adopted by a number of vendors, including Apple Computer and SunMicrosystems, Inc. See also C, Objective-C,object-oriented programming.

ISV’s independent software vendors/8dec04

abstract data type/ 2dec04

n. In programming, a data set defined by theprogrammer in terms of the information it cancontain and the operations that can beperformed with it. An abstract data type is moregeneralized than a data type constrained by the

properties of the objects it contains-for example,the data type "pet" is more generalized than thedata types "pet dog," "pet bird," and "pet fish."The standard example used in illustrating anabstract data type is the stack", a small portionof memory used to store information, generally

on a temporary basis. As an abstract data type,the stack is simply a structure onto which valuescan be pushed (added) and from which they canbe popped (removed). The type of value, suchas integer, is irrelevant to the definition.



The way in which the program performsoperations on abstract data types isencapsulated, or hidden, from the rest of the

program. Encapsulation enables theprogrammer to change the definition of the datatype or its operations without introducing errorsto the existing code that uses the abstract datatype. Abstract data types represent anintermediate step between traditional

programming and object-oriented programming.See also data type, object-orientedprogramming.

encapsulation

n. In object-oriented programming, the

packaging of attributes (properties) andfunctionality (methods or behaviors) to createan object that is essentially a black box —onewhose internal structure remains private andwhose services can be accessed by other objectsonly through messages passed via a clearlydefined interface (the programming equivalentof a mailbox or telephone line). Encapsulationensures that the object providing service canprevent other objects from manipulating its dataor procedures directly, and it enables the object



requesting service to ignore the details of howthat service is provided. See also informationhiding.

fuzzy logic

n. A form of logic used in some expert systemsand other artificial-intelligence applications inwhich variables can have degrees of truthfulnessor falsehood represented by a range of values

between 1 (true) and 0 (false). With fuzzy logic,the outcome of an operation can be expressedas a probability rather than as a certainty. Forexample, an outcome might be probably true,possibly true, possibly false, or probably false.See also expert system.

expert system

n. An application program that makes decisionsor solves problems in a particular field, such asfinance or medicine, by using knowledge andanalytical rules defined by experts in the field. Ituses two components, a knowledge base and aninference engine, to form conclusions. Additionaltools include user interfaces and explanationfacilities, which enable the system to justify orexplain its conclusions as well as allowing



developers to run checks on the operatingsystem. See also artificial intelligence, inferenceengine, intelligent database, encapsulation

n. In object-oriented programming, thepackaging of attributes (properties) andfunctionality (methods or behaviors) to createan object that is essentially a black box —onewhose internal structure remains private andwhose services can be accessed by other objectsonly through messages passed via a clearlydefined interface (the programming equivalentof a mailbox or telephone line). Encapsulationensures that the object providing service canprevent other objects from manipulating its dataor procedures directly, and it enables the object


encapsulate

vb. 1. To treat a collection of structured

information as a whole without affecting ortaking notice of its internal structure. Incommunications, a message or packetconstructed according to one protocol, such as aTCP/IP packet, may be taken with its formatting



data as an undifferentiated stream of bits that isthen broken up and packaged according to alower-level protocol (for example, as ATM

packets) to be sent over a particular network; atthe destination, the lower-level packets areassembled, re-creating the message asformatted for the encapsulated protocol. Seealso ATM (definition 1). 2. In object-orientedprogramming, to keep the implementation

details of a class a separate file whose contentsdo not need to be known by a programmerusing that class. See also object-orientedprogramming, TCP/IP.



SensorNotes(ForDawMyaMyaWin)

sensor

n. A device that detects or measures something by converting nonelectrical energy to

electrical energy. A photocell, for example, detects or measures light by converting it toelectrical energy. See also transducer.

sensor glove

n. A hand-worn computer input device for virtual-reality environments. The glove

translates finger movements by the user to commands for manipulating objects in the

environment. Also called data glove. See also virtual reality.

transducer

n. A device that converts one form of energy into another. Electronic transducers eitherconvert electric energy to another form of energy or convert nonelectric to electric

energy.

virtual reality

n. A simulated 3-D environment that a user can experience and manipulate as if it were

physical. The user sees the environment on display screens, possibly mounted in a special

pair of goggles. Special input devices, such as gloves or suits fitted with motion sensors,

detect the user's actions. Acronym: VR.

information hiding

n. A design practice in which implementationdetails for both data structures and algorithms

within a module or subroutine are hidden fromroutines using that module or subroutine, so asto ensure that those routines do not depend onsome particular detail of the implementation. Intheory, information hiding allows the module or



subroutine to be changed without breaking theroutines that use it. See also break , module,routine, subroutine.

module

n. 1. In programming, a collection of routinesand data structures that performs a particulartask or implements a particular abstract datatype. Modules usually consist of two parts: an

interface, which lists the constants, data types,variables, and routines that can be accessed byother modules or routines, and animplementation, which is private (accessible onlyto the module) and which contains the sourcecode that actually implements the routines in

the module. See also abstract data type,information hiding, Modula-2, modularprogramming. 2. In hardware, a self-containedcomponent that can provide a complete functionto a system and can be interchanged with othermodules that provide similar functions. See alsomemory card, SIMM.

interface

n. 1. The point at which a connection is madebetween two elements so that they can work



n. A visual computer environment thatrepresents programs, files, and options withgraphical images, such as icons, menus, and

dialog boxes on the screen. The user can selectand activate these options by pointing andclicking with a mouse or, often, with thekeyboard. A particular item (such as a scroll bar)works the same way to the user in allapplications, because the graphical user

interface provides standard software routines tohandle these elements and report the user'sactions (such as a mouse click on a particularicon or at a particular location in text, or a keypress); applications call these routines withspecific parameters rather than attempting toreproduce them from scratch. Acronym: GUI.

operating system

n. The software that controls the allocation andusage of hardware resources such as memory,central processing unit (CPU) time, disk space,and peripheral devices. The operating system isthe foundation software on which applicationsdepend. Popular operating systems includeWindows 98, Windows NT, Mac OS, and UNIX.

Acronym: OS. Also called executive.



virtual

adj. Of or pertaining to a device, service, or

sensory input that is perceived to be what it isnot in actuality, usually as more "real" orconcrete than it actually is.

polymorphism

n. In an object-oriented programming language,

the ability to redefine a routine in a derived class(a class that inherited its data structures androutines from another class). Polymorphismallows the programmer to define a base classthat includes routines that perform standardoperations on groups of related objects, withoutregard to the exact type of each object. The

programmer then redefines the routines in thederived class for each type, taking into accountthe characteristics of the object. See also class,derived class, object (definition 2), object-oriented programming.

programmable interrupt controller

n. An Intel chip that handles interrupt requests(IRQs). IBM AT machines use twoprogrammable interrupt controllers to



accommodate a maximum of 15 IRQs. Theprogrammable interrupt controller has beenreplaced by the advanced programmable

interrupt controller (APIC), which supportsmultiprocessing. Acronym: PIC. See also IBM

AT, IRQ

spam1

n. An unsolicited e-mail message sent to many

recipients at one time, or a news article postedsimultaneously to many newsgroups. Spam isthe electronic equivalent of junk mail. In mostcases, the content of a spam message or articleis not relevant to the topic of the newsgroup orthe interests of the recipient; spam is an abuse

of the Internet in order to distribute a message(usually commercial or religious) to a hugenumber of people at minimal cost.

spam2

vb. To distribute unwanted, unrequested mailwidely on the Internet by posting a message totoo many recipients or too many newsgroups.The act of distributing such mail, known asspamming, angers most Internet users and hasbeen known to invite retaliation, often in the



computer graphics, a special effect orproduction effect that is applied to bitmappedimages; for example, shifting pixels within an

image, making elements of the imagetransparent, or distorting the image. Somefilters are built into a graphics program, such asa paint program or an image editor. Others areseparate software packages that plug into thegraphics program. See also bitmapped graphics,

image editor, paint program.

e-mail filter

n. A feature in e-mail-reading software thatautomatically sorts incoming mail into differentfolders or mailboxes based on information

contained in the message. For example, allincoming mail from a user's Uncle Joe might beplaced in a folder labeled "Uncle Joe". Filtersmay also be used either to block or accept e-mail from designated sources.

n. Short for picture (pix) element. One spot in a

rectilinear grid of thousands of such spots thatare individually "painted" to form an imageproduced on the screen by a computer or onpaper by a printer. A pixel is the smallestelement that display or print hardware and



software can manipulate in creating letters,numbers, or graphics. Also called pel.

pixel imagen. The representation of a color graphic in acomputer's memory. A pixel image is similar to abit image, which also describes a screengraphic, but a pixel image has an addeddimension, sometimes called depth, that

describes the number of bits in memoryassigned to each on-screen pixel.

pixel map

n. A data structure that describes the pixelimage of a graphic, including such features as

color, image, resolution, dimensions, storageformat, and number of bits used to describeeach pixel. See also pixel, pixel image.

31dec05

BIOS

n. Acronym for basic input/output system. OnPC-compatible computers, the set of essentialsoftware routines that tests hardware at startup,starts the operating system, and supports the



transfer of data among hardware devices. TheBIOS is stored in read-only memory (ROM) sothat it can be executed when the computer is

turned on. Although critical to performance, theBIOS is usually invisible to computer users. Seealso AMI BIOS, CMOS setup, Phoenix BIOS,ROM BIOS. Compare Toolbox.

flip-flop

n. A circuit that alternates between two possiblestates when a pulse is received at the input. Forexample, if the output of a flip-flop is high and apulse is received at the input, the output "flips"to low; a second input pulse "flops" the outputback to high, and so on. Also called bistable

multivibratorfloat

n. The data type name used in someprogramming languages, notably C, to declarevariables that can store floating-point numbers.See also data type, floating-point number,variable

floating-point number



n. A number represented by a mantissa and anexponent according to a given base. Themantissa is usually a value between 0 and 1. To

find the value of a floating-point number, thebase is raised to the power of the exponent, andthe mantissa is multiplied by the result. Ordinaryscientific notation uses floating-point numberswith 10 as the base. In a computer, the base forfloating-point numbers is usually 2.

floating-point operation

n. An arithmetic operation performed on datastored in floating-point notation. Floating-pointoperations are used wherever numbers mayhave either fractional or irrational parts, as in

spreadsheets and computer-aided design (CAD).Therefore, one measure of a computer's poweris how many millions of floating-point operationsper second (MFLOPS or megaflops) it canperform. Acronym: FLOP. Also called floating-point operation. See also floating-point notation,MFLOfloating-point notation

n. A numeric format that can be used torepresent very large real numbers and verysmall real numbers. Floating-point numbers arestored in two parts, a mantissa and an



exponent. The mantissa specifies the digits inthe number, and the exponent specifies themagnitude of the number (the position of the

decimal point). For example, the numbers314,600,000 and 0.0000451 are expressedrespectively as 3146E5 and 451E-7 in floating-point notation. Most microprocessors do notdirectly support floating-point arithmetic;consequently, floating-point calculations are

performed either by using software or with aspecial floating-point processor. Also calledexponential notation. See also fixed-pointnotation, floating-point processor, integer.

fixed-point notation

n. A numeric format in which the decimal pointhas a specified position. Fixed-point numbersare a compromise between integral formats,which are compact and efficient, and floating-point numeric formats, which have a greatrange of values. Like floating-point numbers,fixed-point numbers can have a fractional part,but operations on fixed-point numbers usuallytake less time than floating-point operations.See also floating-point notation, integer.

integer



n. 1. A positive or negative "whole" number,such as 37, -50, or 764. 2. A data typerepresenting whole numbers. Calculations

involving only integers are much faster thancalculations involving floating-point numbers, sointegers are widely used in programming forcounting and numbering purposes. Integers canbe signed (positive or negative) or unsigned(positive). They can also be described as long or

short, depending on the number of bytesneeded to store them. Short integers, stored in2 bytes, cover a smaller range of numbers (forexample, -32,768 through 32,767) than do longintegers (for example, -2,147,483,648 through2,147,483,647), which are stored in 4 bytes.

Also called integral number. See also floating-point notation

byte

n. Short for binary term. A unit of data, todayalmost always consisting of 8 bits. A byte canrepresent a single character, such as a letter, adigit, or a punctuation mark. Because a byterepresents only a small amount of information,amounts of computer memory and storage areusually given in kilobytes (1,024 bytes),



megabytes (1,048,576 bytes), or gigabytes(1,073,741,824 bytes). Abbreviation: B. See alsobit, gigabyte, kilobyte, megabyte. Compare

octet, word.

character

n. A letter, number, punctuation mark, or othersymbol or control code that is represented to acomputer by one unit-1 byte-of information. A

character is not necessarily visible, either on thescreen or on paper; a space, for example, is asmuch a character as is the letter a or any of thedigits 0 through 9. Because computers mustmanage not only so-called printable charactersbut also the look (formatting) and transfer of

electronically stored information, a character canadditionally indicate a carriage return or aparagraph mark in a word-processed document.It can be a signal to sound a beep, begin a newpage, or mark the end of a file. See also ASCII,control character, EBCDIC.

nibble or nybble

n. Half a byte (4 bits). Compare quadbit.

ascii



range from 0 to 127. Most PC-based systemsuse an 8-bit extended ASCII code, with an extra128 characters used to represent special

symbols, foreign-language characters, andgraphic symbols. See also ASCII, character,EBCDIC, extended ASCII, standard ASCII.

extended ASCII

n. Any set of characters assigned to ASCII

values between decimal 128 and 255(hexadecimal 80 through FF). The specificcharacters assigned to the extended ASCIIcodes vary between computers and betweenprograms, fonts, or graphics characters.Extended ASCII adds capability by allowing for

128 additional characters, such as accentedletters, graphics characters, and specialsymbols. See also ASCII.

C++

n. An object-oriented version of the Cprogramming language, developed by BjarneStroustrup in the early 1980s at BellLaboratories and adopted by a number of vendors, including Apple Computer and Sun



Microsystems, Inc. See also C, Objective-C,object-oriented programming.

object-oriented programmingn. A programming paradigm in which a programis viewed as a collection of discrete objects thatare self-contained collections of data structuresand routines that interact with other objects.

Acronym: OOP. See also C++, object (definition

2), Objective-C.

object-oriented programming

n. A programming paradigm in which a programis viewed as a collection of discrete objects thatare self-contained collections of data structures

and routines that interact with other objects. Acronym: OOP. See also C++, object (definition2), Objective-C.

object

n. 1. Short for object code (machine-readable

code). 2. In object-oriented programming, avariable comprising both routines and data thatis treated as a discrete entity. See also abstractdata type, module (definition 1), object-orientedprogramming. 3. In graphics, a distinct entity.



For example, a bouncing ball might be an objectin a graphics program.

modulen. 1. In programming, a collection of routinesand data structures that performs a particulartask or implements a particular abstract datatype. Modules usually consist of two parts: aninterface, which lists the constants, data types,

variables, and routines that can be accessed byother modules or routines, and animplementation, which is private (accessible onlyto the module) and which contains the sourcecode that actually implements the routines inthe module. See also abstract data type,

information hiding, Modula-2, modularprogramming. 2. In hardware, a self-containedcomponent that can provide a complete functionto a system and can be interchanged with othermodules that provide similar functions. See alsomemory card, SIMM.

abstract data type

n. In programming, a data set defined by theprogrammer in terms of the information it cancontain and the operations that can be



performed with it. An abstract data type is moregeneralized than a data type constrained by theproperties of the objects it contains-for example,

the data type "pet" is more generalized than thedata types "pet dog," "pet bird," and "pet fish."The standard example used in illustrating anabstract data type is the stack", a small portionof memory used to store information, generallyon a temporary basis. As an abstract data type,

the stack is simply a structure onto which valuescan be pushed (added) and from which they canbe popped (removed). The type of value, suchas integer, is irrelevant to the definition.

The way in which the program performsoperations on abstract data types is

encapsulated, or hidden, from the rest of theprogram. Encapsulation enables theprogrammer to change the definition of the datatype or its operations without introducing errorsto the existing code that uses the abstract datatype. Abstract data types represent an

intermediate step between traditionalprogramming and object-oriented programming.See also data type, object-orientedprogramming.



data type

n. In programming, a definition of a set of data

that specifies the possible range of values of theset, the operations that can be performed onthe values, and the way in which the values arestored in memory. Defining the data type allowsa computer to manipulate the dataappropriately. Data types are most oftensupported in high-level languages and ofteninclude types such as real, integer, floatingpoint, character, Boolean, and pointer. How alanguage handles data typing is one of its majorcharacteristics. See also cast, constant,enumerated data type, strong typing, typechecking, user-defined data type, variable, weak

typing.

toolbox

n. A set of predefined (and usually precompiled)routines a programmer can use in writing aprogram for a particular machine, environment,

or application. Also called toolkit. See also library (definition 1).

Toolbox



n. A set of routines stored mostly in the read-only memory of a Macintosh that providesapplication programmers with the tools needed

to support the graphical interface characteristicof the computer. Also called User InterfaceToolbox.

disk drive

n. An electromechanical device that reads fromand writes to disks. The main components of adisk drive include a spindle on which the disk ismounted, a drive motor that spins the disk whenthe drive is in operation, one or more read/writeheads, a second motor that positions the

read/write head(s) over the disk, and controllercircuitry that synchronizes read/write activitiesand transfers information to and from thecomputer. Two types of disk drives are incommon use: floppy disk drives and hard disk drives. Floppy disk drives are designed to accept

removable disks in either 5.25-inch or 3.5-inchformat; hard disk drives are faster, high-capacitystorage units that are completely enclosed in aprotective case.



paradigm

n. An archetypal example or pattern that

provides a model for a process or systemarchitecture

n. 1. The physical construction or design of acomputer system and its components. See alsocache, CISC, closed architecture, network

architecture, open architecture, pipelining, RISC.2. The data-handling capacity of amicroprocessor. 3. The design of applicationsoftware incorporating protocols and the meansfor expansion and interfacing with otherprograms.

cache

\kash\ n. A special memory subsystem in whichfrequently used data values are duplicated forquick access. A memory cache stores thecontents of frequently accessed RAM locationsand the addresses where these data items are

stored. When the processor references anaddress in memory, the cache checks to seewhether it holds that address. If it does hold theaddress, the data is returned to the processor; if



it does not, a regular memory access occurs. A cache is useful when RAM accesses are slowcompared with the microprocessor speed,

because cache memory is always faster thanmain RAM memory. See also disk cache, waitstate.

disk

n. 1. A round, flat piece of flexible plastic coated

with a magnetic material that can be electricallyinfluenced to hold information recorded in digital(binary) form and encased in a protective plastic

jacket to protect them from damage andcontamination. Also called floppy, floppy disk,microfloppy disk. Compare compact disc, disc. 2.

See hard drive compact disc

n. 1. An optical storage medium for digital data,usually audio. A compact disc is a nonmagnetic,polished metal disc with a protective plasticcoating that can hold up to 74 minutes of high-fidelity recorded sound. The disk is read by anoptical scanning mechanism that uses a high-intensity light source, such as a laser, andmirrors. Also called optical disc. 2. A technology



that forms the basis of media such as CD-ROM,CD-ROM/XA, CD-I, CD-R, DVI, and PhotoCD.These media are all compact disc-based but

store various types of digital information andhave different read/write capabilities.Documentation for compact disc formats can befound in books designated by the color of theircovers. For example, documentation for audiocompact discs is found in the Red Book. See

also CD-I, CD-R , CD-ROM, CD-ROM/XA , DVI,Green Book (definition 2), Orange Book (definition 2), PhotoCD, Red Book (definition 2).3. See CD.

disc

n. A round, flat piece of nonmagnetic, shinymetal encased in a plastic coating, designed tobe read from and written to by optical (laser)technology. It is now standard practice to usethe spelling disc for optical discs and disk in allother computer contexts, such as floppy disk,hard disk, and RAM disk. See also compact disc.

RS-232-C standard

n. An accepted industry standard for serialcommunications connections. Adopted by the



Electrical Industries Association, thisRecommended Standard (RS) defines thespecific lines and signal characteristics used by

serial communications controllers to standardizethe transmission of serial data between devices.The letter C denotes that the current version of the standard is the third in a series. See alsoCTS, DSR , DTR , RTS, RXD, TXD.

interactive processing

n. Processing that involves the more or lesscontinuous participation of the user. Such acommand/response mode is characteristic of microcomputers. Compare batch processing (definition 2).

interactive program

n. A program that exchanges output and inputwith the user, who typically views a display of some sort and uses an input device, such as akeyboard, mouse, or joystick, to provideresponses to the program. A computer game isan interactive program. Compare batchprogram.

handshake



n. A series of signals acknowledging thatcommunication or the transfer of informationcan take place between computers or other

devices. A hardware handshake is an exchangeof signals over specific wires (other than thedata wires), in which each device indicates itsreadiness to send or receive data. A softwarehandshake consists of signals transmitted overthe same wires used to transfer data, as in

modem-to-modem communications overtelephone lines.

31dec05

communications protocol

n. A set of rules or standards designed to enable

computers to connect with one another and toexchange information with as little error aspossible. The protocol generally accepted forstandardizing overall computer communicationsis a seven-layer set of hardware and softwareguidelines known as the OSI (Open Systems

Interconnection) model. A somewhat differentstandard, widely used before the OSI model wasdeveloped, is IBM's SNA (Systems Network

Architecture). The word protocol is often used,sometimes confusingly, in reference to a



multitude of standards affecting differentaspects of communication, such as file transfer(for example, XMODEM and ZMODEM),

handshaking (for example, XON/XOFF), andnetwork transmissions (for example, CSMA/CD).See also ISO/OSI model, SNA .

1jan2006

spam1

n. An unsolicited e-mail message sent to manyrecipients at one time, or a news article postedsimultaneously to many newsgroups. Spam isthe electronic equivalent of junk mail. In most

cases, the content of a spam message or articleis not relevant to the topic of the newsgroup orthe interests of the recipient; spam is an abuseof the Internet in order to distribute a message(usually commercial or religious) to a hugenumber of people at minimal cost.

spam2

vb. To distribute unwanted, unrequested mailwidely on the Internet by posting a message totoo many recipients or too many newsgroups.



The act of distributing such mail, known asspamming, angers most Internet users and hasbeen known to invite retaliation, often in the

form of return spamming that can flood andpossibly disable the electronic mailbox of theoriginal spammer

6jan06

SDSL

n. Acronym for symmetric (or single-line) digitalsubscriber line, a digital telecommunicationstechnology that is a variation of HDSL. SDSLuses one pair of copper wire rather than twopairs of wires and transmits at 1.544 Mbps.Compare ADSL.

VoIP

n. Acronym for Voice over IP. The use of theInternet Protocol (IP) for transmitting voicecommunications. VoIP delivers digitized audio inpacket form and can be used for transmitting

over intranets, extranets, and the Internet. It isessentially an inexpensive alternative totraditional telephone communication over thecircuit-switched Public Switched Telephone



Network (PSTN). VoIP covers computer-to-computer, computer-to-telephone, andtelephone-based communications. For the sake

of compatibility and interoperability, a groupcalled the VoIP Forum promotes productdevelopment based on the ITU-T H.323standard for transmission of multimedia over theInternet. Also called Internet telephony. Seealso H.323.

Micro Channel Architecture

n. The design of the bus in IBM PS/2 computers(except Models 25 and 30). The Micro Channelis electrically and physically incompatible withthe IBM PC/AT bus. Unlike the PC/AT bus, the

Micro Channel functions as either a 16-bit or a32-bit bus. The Micro Channel also can bedriven independently by multiple bus masterprocessors.

PS/2 bus

n. See Micro Channel Architecture.

bus

n. A set of hardware lines (conductors) used fordata transfer among the components of a



computer system. A bus is essentially a sharedhighway that connects different parts of thesystem-including the processor, disk-drive

controller, memory, and input/output ports-andenables them to transfer information. The busconsists of specialized groups of lines that carrydifferent types of information. One group of lines carries data; another carries memoryaddresses (locations) where data items are to be

found; yet another carries control signals. Busesare characterized by the number of bits they cantransfer at a single time, equivalent to thenumber of wires within the bus. A computerwith a 32-bit address bus and a 16-bit data bus,for example, can transfer 16 bits of data at atime from any of 232 memory locations. MostPCs contain one or more expansion slots intowhich additional boards can be plugged toconnect them to the bus.

hard disk

n. A device containing one or more inflexibleplatters coated with material in which data canbe recorded magnetically, together with theirread/write heads, the head-positioningmechanism, and the spindle motor in a sealed



case that protects against outside contaminants.The protected environment allows the head tofly 10 to 25 millionths of an inch above the

surface of a platter rotating typically at 3,600 to7,200 rpm; therefore, much more data can bestored and accessed much more quickly than ona floppy disk. Most hard disks contain from twoto eight platters. Also called hard disk drive.Compare floppy disk .

soft copy

n. The temporary images presented on acomputer display screen. Compare hard copy.

hard copy

n. Printed output on paper, film, or otherpermanent medium. Compare soft copy.

URL

n. Acronym for Uniform Resource Locator. Anaddress for a resource on the Internet. URLs are

used by Web browsers to locate Internetresources. A URL specifies the protocol to beused in accessing the resource (such as http: fora World Wide Web page or ftp: for an FTP site),the name of the server on which the resource



resides (such as //www.whitehouse.gov), and,optionally, the path to a resource (such as anHTML document or a file on that server). See

also FTP1 (definition 1), HTML, HTTP, path (definition 1), server (definition 2), virtual path (definition 1), Web browser.

HDSL

n. Acronym for High-bit-rate Digital Subscriber

Line. A form of DSL, HDSL is a protocol fordigital transmission of data over standardcopper telecommunications lines (as opposed tofiber-optic lines) at rates of 1.544 Mbps in bothdirections. Also called High-data-rate DigitalSubscriber Line. See also DSL.

broadband

adj. Of or relating to communications systems inwhich the medium of transmission (such as awire or fiber-optic cable) carries multiplemessages at a time, each message modulatedon its own carrier frequency by means of modems. Broadband communication is found inwide area networks. Compare baseband.

8JAN06



grid pad to detect motion. The two lights are of different colors, and the special mouse pad hasa grid of lines in the same colors, one color for

vertical lines and another for horizontal lines.Light detectors paired with the LEDs sense whena colored light passes over a line of the samecolor, indicating the direction of movement. Seealso mouse. Compare mechanical mouse,optomechanical mouse.

fiber optics

n. A technology for the transmission of lightbeams along optical fibers. A light beam, suchas that produced in a laser, can be modulated tocarry information. Because light has a higher

frequency on the electromagnetic spectrum thanother types of radiation, such as radio waves, asingle fiber-optic channel can carry significantlymore information than most other means of information transmission. Optical fibers are thinstrands of glass or other transparent material,with dozens or hundreds of strands housed in asingle cable. Optical fibers are essentiallyimmune to electromagnetic interference. Seealso optical fiber.

mechanical mouse



difficult, although advances are being made inthis area. Also called speech recognition. Seealso artificial intelligence, dictation software,

neural network .

neural network

n. A type of artificial-intelligence systemmodeled after the neurons (nerve cells) in abiological nervous system and intended to

simulate the way a brain processes information,learns, and remembers. A neural network isdesigned as an interconnected system of processing elements, each with a limitednumber of inputs and an output. Theseprocessing elements are able to "learn" by

receiving weighted inputs that, with adjustment,time, and repetition, can be made to produceappropriate outputs. Neural networks are usedin areas such as pattern recognition, speechanalysis, and speech synthesis. See also artificialintelligence, pattern recognition (definition 1).

pattern recognition

n. 1. A broad technology describing the ability of a computer to identify patterns. The termusually refers to computer recognition of visual



images or sound patterns that have beenconverted to arrays of numbers. 2. Therecognition of purely mathematical or textual

patterns.

thumbnail

n. A miniature version of an image or electronicversion of a page that is generally used to allowquick browsing through multiple images or

pages. For example, Web pages often containthumbnails of images (which can be loadedmuch more quickly by the Web browser than thefull-size image). Many of these thumbnails canbe clicked on to load the complete version of theimage

25jan06wednes

ADSL

n. Acronym for asymmetric digital subscriberline. Technology and equipment allowing high-speed digital communication, including video

signals, across an ordinary twisted-pair copperphone line, with speeds up to 8 Mbps (megabitsper second) downstream (to the customer) andup to 640 Kbps (kilobits per second) upstream.



ADSL access to the Internet is offered by someregional telephone companies, offering usersfaster connection times than those available

through connections made over standard phonelines. Also called asymmetric digital subscriberloop. Compare SDSL.

Post Office Protocol

n. A protocol for servers on the Internet that

receive, store, and transmit e-mail and forclients on computers that connect to the serversto download and upload e-mail. Acronym: POP.

25jan06

digital signal processor

n. An integrated circuit designed for high-speeddata manipulation and used in audio,communications, image manipulation, and otherdata acquisition and data control applications.

Acronym: DSP

hardwaren. The physical components of a computersystem, including any peripheral equipment such



as printers, modems, and mouse devices.Compare firmware, software

26jan06

cookie

n. 1. A block of data that a server returns to aclient in response to a request from the client. 2.

On the World Wide Web, a block of data that aWeb server stores on a client system. When auser returns to the same Web site, the browsersends a copy of the cookie back to the server.Cookies are used to identify users, to instructthe server to send a customized version of the

requested Web page, to submit accountinformation for the user, and for otheradministrative purposes. 3. Originally an allusionto fortune cookie, a UNIX program that outputsa different message, or "fortune", each time it isused. On some systems, the cookie program isrun during user logon.

cache

\kash\ n. A special memory subsystem in whichfrequently used data values are duplicated for



quick access. A memory cache stores thecontents of frequently accessed RAM locationsand the addresses where these data items are

stored. When the processor references anaddress in memory, the cache checks to seewhether it holds that address. If it does hold theaddress, the data is returned to the processor; if it does not, a regular memory access occurs. A cache is useful when RAM accesses are slow

compared with the microprocessor speed,because cache memory is always faster thanmain RAM memory. See also disk cache, waitstate.

benchmark 1

n. A test used to measure hardware or softwareperformance. Benchmarks for hardware useprograms that test the capabilities of theequipment-for example, the speed at which aCPU can execute instructions or handle floating-point numbers. Benchmarks for softwaredetermine the efficiency, accuracy, or speed of aprogram in performing a particular task, such asrecalculating data in a spreadsheet. The samedata is used with each program tested, so theresulting scores can be compared to see which



programs perform well and in what areas. Thedesign of fair benchmarks is something of anart, because various combinations of hardware

and software can exhibit widely variableperformance under different conditions. Often,after a benchmark has become a standard,developers try to optimize a product to run thatbenchmark faster than similar products run it inorder to enhance sales. See also sieve of

Eratosthenes.

benchmark 2

vb. To measure the performance of hardware orsoftware.

benign virus

n. A program that exhibits properties of a virus,such as self-replication, but does not otherwisedo harm to the computer systems that it infects.

2feb06

thumbnailn. A miniature version of an image or electronicversion of a page that is generally used to allowquick browsing through multiple images or



pages. For example, Web pages often containthumbnails of images (which can be loadedmuch more quickly by the Web browser than the

full-size image). Many of these thumbnails canbe clicked on to load the complete version of theimage.

Java

n. An object-oriented programming language

developed by Sun Microsystems. Similar to C++,Java is smaller, more portable, and easier to usethan C++ because it is more robust and itmanages memory on its own. Java was alsodesigned to be secure and platform-neutral(meaning that it can be run on any platform)

through the fact that Java programs arecompiled into bytecode, which is not refined tothe point of relying on platform-specificinstructions and runs on a computer in a specialsoftware environment known as a virtualmachine. This characteristic of Java makes it auseful language for programming Webapplications, since users access the Web frommany types of computers. Java is used inprogramming small applications, or applets, forthe World Wide Web, as well as in creating



distributed network applications. See also bytecode, Java applet, Jini, object-orientedprogramming.

platform

n. 1. The foundation technology of a computersystem. Because computers are layered devicescomposed of a chip-level hardware layer, afirmware and operating-system layer, and an

applications program layer, the bottommostlayer of a machine is often called a platform. 2.In everyday usage, the type of computer oroperating system being used.

transducer

n. A device that converts one form of energyinto another. Electronic transducers eitherconvert electric energy to another form of energy or convert nonelectric to electric energy.

IDE

n. Acronym for Integrated Device Electronics. A type of disk-drive interface in which thecontroller electronics reside on the drive itself,eliminating the need for a separate adaptercard. The IDE interface is compatible with the



n. 1. A device or program routine that convertscoded data back to its original form. This canmean changing unreadable or encrypted codes

into readable text or changing one code toanother, although the latter type of decoding isusually referred to as conversion. Compare conversion. 2. In electronics and hardware, atype of circuit that produces one or moreselected output signals based on the

combination of input signals it receives.

Wednesday, March 28, 2007

|NotesMemory

flash memoryn. A type of nonvolatile memory. Flash memoryis similar to EEPROM memory in function but itmust be erased in blocks, whereas EEPROM canbe erased one byte at a time. Because of itsblock-oriented nature, flash memory iscommonly used as a supplement to orreplacement for hard disks in portablecomputers. In this context, flash memory eitheris built into the unit or, more commonly, is



available as a PC Card that can be plugged intoa PCMCIA slot. A disadvantage of the block-oriented nature of flash memory is that it cannot

be practically used as main memory (RAM)because a computer needs to be able to write tomemory in single-byte increments. See alsoEEPROM, nonvolatile memory

nonvolatile memory

n. A storage system that does not lose datawhen power is removed from it. Intended torefer to core memory, ROM, EPROM, flashmemory, bubble memory, or battery-backedCMOS RAM, the term is occasionally used inreference to disk subsystems as well. See alsobubble memory, CMOS RAM, core, EPROM, flashmemory 19Octo04

contiguous data structure/10nov04n. A data structure, such as an array, that isstored in a consecutive set of memory locations.See also data structure. Compare noncontiguous

data structure.noncontiguous data structure/10nov04n. In programming, a data structure whoseelements are not stored contiguously in



memory. Data structures such as graphs andtrees, whose elements are connected bypointers, are noncontiguous data structures.

Compare contiguous data structure.Bit/10nov04n. Short for binary digit. The smallest unit of information handled by a computer. One bitexpresses a 1 or a 0 in a binary numeral, or atrue or false logical condition, and is represented

physically by an element such as a high or lowvoltage at one point in a circuit or a small spoton a disk magnetized one way or the other. A single bit conveys little information a humanwould consider meaningful. A group of 8 bits,however, makes up a byte, which can be usedto represent many types of information, such asa letter of the alphabet, a decimal digit, or othercharacter. See also ASCII, binary1, bytebyte/10nov04n. Short for binary term. A unit of data, todayalmost always consisting of 8 bits. A byte canrepresent a single character, such as a letter, a

digit, or a punctuation mark. Because a byterepresents only a small amount of information,amounts of computer memory and storage areusually given in kilobytes (1,024 bytes),



megabytes (1,048,576 bytes), or gigabytes(1,073,741,824 bytes). Abbreviation: B. See alsobit, gigabyte, kilobyte, megabyte. Compare

octet, word.

flash memoryn. A type of nonvolatile memory. Flash memoryis similar to EEPROM memory in function but itmust be erased in blocks, whereas EEPROM can

be erased one byte at a time. Because of itsblock-oriented nature, flash memory iscommonly used as a supplement to orreplacement for hard disks in portablecomputers. In this context, flash memory eitheris built into the unit or, more commonly,

is available as a PC Card that can be pluggedinto a PCMCIA slot. A disadvantage of the block-oriented nature of flash memory is that it cannotbe practically used as main memory (RAM)because a computer needs to be able to write tomemory in single-byte increments. See also

EEPROM, nonvolatile memory, PC Card, PCMCIA slot.

kernel



n. The core of an operating system-the portionof the system that manages memory, files, andperipheral devices; maintains the time and date;

launches applications; and allocates systemresources.

Wednesday, May 02, 2007

Linux

n. A version of the UNIX System V Release 3.0kernel developed for PCs with 80386 and higher-level microprocessors. Developed by LinusTorvalds (for whom it is named) along withnumerous collaborators worldwide, Linux isdistributed free, and its source code is open tomodification by anyone who chooses to work on

it, although some companies distribute it as partof a commercial package with Linux-compatibleutilities. The Linux kernel works with the GNUutilities developed by the Free SoftwareFoundation, which did not produce a kernel. It isused by some as an operating system for

network servers and in the 1998/1999timeframe began to gain increased visibilitythrough support from vendors such as IBM andCompaq. See also free software, GNU, kernel,UNIX.



UNIX

n. A multiuser, multitasking operating system.

Originally developed by Ken Thompson andDennis Ritchie at AT&T Bell Laboratories from1969 through 1973 for use on minicomputers,UNIX has evolved into a complex, powerfuloperating system that, because it is written inthe C language, is more portable-that is, lessmachine-specific-than many other operatingsystems. UNIX has been released in a widevariety of versions, or flavors, including System

V (developed by AT&T for commercial release;many current flavors on based on it), BSD UNIX(freeware developed at the University of California Berkeley, which has spun off many

related flavors) AIX (a version of System Vadapted by IBM to run on RISC-basedworkstations), A/UX (a graphical version for theMacintosh), Linux (a newer version that runs onthe Intel chip), and SunOS (based on BSD UNIXand available on Sun workstations). Many

flavors of UNIX are available free. With someflavors, the source code is also free, making itan instrumental part of the Open Sourcemovement. UNIX is a widely used as a network operating system, especially in conjunction with



the Internet. See also BSD UNIX, Linux, opensource, System V.

open sourcen. The practice of making the source code(program instructions) for a software productfreely available, at no cost, to interested usersand developers, even though they were notinvolved in creating the original product. The

distributors of open source software expect andencourage users and outside programmers toexamine the code in order to identify problems,and to modify the code with suggestedimprovements and enhancements. Widely usedopen-source products include the Linux

operating system and the Apache web server.open system

n. 1. In communications, a computer network designed to incorporate all devices-regardless of the manufacturer or model-that can use thesame communications facilities and protocols. 2.In reference to computer hardware or software,a system that can accept add-ons produced bythird-party suppliers. See also open architecture (definition 1).



open architecture

n. 1. Any computer or peripheral design that has

published specifications. A publishedspecification lets third parties develop add-onhardware for a computer or device. Compare closed architecture (definition 1). 2. A designthat provides for expansion slots on themotherboard, thereby allowing the addition of boards to enhance or customize a system.Compare closed architecture (definition 2).

closed architecture

n. 1. Any computer design whose specificationsare not freely available. Such proprietaryspecifications make it difficult or impossible for

third-party vendors to create ancillary devicesthat work correctly with a closed-architecturemachine; usually only its original maker canbuild peripherals and add-ons for such amachine. Compare open architecture (definition1). 2. A computer system that provides no

expansion slots for adding new types of circuitboards within the system unit. The original

Apple Macintosh was an example of a closedarchitecture. Compare open architecture (definition 2).



operating system

n. The software that controls the allocation and

usage of hardware resources such as memory,central processing unit (CPU) time, disk space,and peripheral devices. The operating system isthe foundation software on which applicationsdepend. Popular operating systems includeWindows 98, Windows NT, Mac OS, and UNIX. Acronym: OS. Also called executive.

RAM

n. Acronym for random access memory.Semiconductor-based memory that can be readand written by the central processing unit (CPU)or other hardware devices. The storage

locations can be accessed in any order. Notethat the various types of ROM memory arecapable of random access but cannot be writtento. The term RAM, however, is generallyunderstood to refer to volatile memory that canbe written to as well as read. Compare core,

EPROM, flash memory, PROM, ROM (definition2).

ROM



n. 1. Acronym for read-only memory. A semiconductor circuit into which code or data ispermanently installed by the manufacturing

process. The use of this technology iseconomically viable only if the chips areproduced in large quantities; experimentaldesigns or small volumes are best handled usingPROM or EPROM. 2. Acronym for read-onlymemory. Any semiconductor circuit serving as a

memory that contains instructions or data thatcan be read but not modified (whether placedthere by manufacturing or by a programmingprocess, as in PROM and EPROM). See also EEPROM, EPROM, PROM

volati le memory

n. 1. Memory, such as RAM, that loses its datawhen the power is shut off. Compare nonvolatilememory. 2. Memory used by a program that canchange independently of the program, such asmemory shared by another program or by aninterrupt service routine.

nonvolatile memory

n. A storage system that does not lose datawhen power is removed from it. Intended to



refer to core memory, ROM, EPROM, flashmemory, bubble memory, or battery-backedCMOS RAM, the term is occasionally used in

reference to disk subsystems as well. See also bubble memory, CMOS RAM, core, EPROM, flashmemory, ROM.

flash memory

n. A type of nonvolatile memory. Flash memory

is similar to EEPROM memory in function but itmust be erased in blocks, whereas EEPROM canbe erased one byte at a time. Because of itsblock-oriented nature, flash memory iscommonly used as a supplement to orreplacement for hard disks in portable

computers. In this context, flash memory eitheris built into the unit or, more commonly, isavailable as a PC Card that can be plugged intoa PCMCIA slot. A disadvantage of the block-oriented nature of flash memory is that it cannotbe practically used as main memory (RAM)because a computer needs to be able to write tomemory in single-byte increments. See also EEPROM, nonvolatile memory, PC Card, PCMCIA slot.

hacker



n. 1. A computerphile; a person who is totallyengrossed in computer technology andcomputer programming or who likes to examine

the code of operating systems and otherprograms to see how they work. 2. A person,more commonly considered a cracker, who usescomputer expertise for illicit ends, such as bygaining access to computer systems withoutpermission and tampering with programs and

data. Also called cracker.

direct memory access29sep04

n. Memory access that does not involve themicroprocessor and is frequently used for datatransfer directly between memory and an

intelligent peripheral device, such as a disk drive. Acronym: DMA.

n. An object-oriented version of the Cprogramming language, developed by BjarneStroustrup in the early 1980s at BellLaboratories and adopted by a number of

vendors, including Apple Computer and SunMicrosystems, Inc. See also C, Objective-C,object-oriented programming.





n. In programming, a data set defined by the

programmer in terms of the information it cancontain and the operations that can beperformed with it. An abstract data type is moregeneralized than a data type constrained by theproperties of the objects it contains-for example,the data type "pet" is more generalized than thedata types "pet dog," "pet bird," and "pet fish."The standard example used in illustrating anabstract data type is the stack", a small portionof memory used to store information, generallyon a temporary basis. As an abstract data type,the stack is simply a structure onto which valuescan be pushed (added) and from which they can

be popped (removed). The type of value, suchas integer, is irrelevant to the definition.

The way in which the program performsoperations on abstract data types isencapsulated, or hidden, from the rest of theprogram. Encapsulation enables theprogrammer to change the definition of the datatype or its operations without introducing errorsto the existing code that uses the abstract datatype. Abstract data types represent an



intermediate step between traditionalprogramming and object-oriented programming.See also data type, object-oriented

programming.

encapsulation

n. In object-oriented programming, thepackaging of attributes (properties) andfunctionality (methods or behaviors) to create

an object that is essentially a black box —onewhose internal structure remains private andwhose services can be accessed by other objectsonly through messages passed via a clearlydefined interface (the programming equivalentof a mailbox or telephone line). Encapsulation

ensures that the object providing service canprevent other objects from manipulating its dataor procedures directly, and it enables the objectrequesting service to ignore the details of howthat service is provided. See also informationhiding.

fuzzy logic

n. A form of logic used in some expert systemsand other artificial-intelligence applications inwhich variables can have degrees of truthfulness



or falsehood represented by a range of valuesbetween 1 (true) and 0 (false). With fuzzy logic,the outcome of an operation can be expressed

as a probability rather than as a certainty. Forexample, an outcome might be probably true,possibly true, possibly false, or probably false.See also expert system.

expert system/ 2dec04

n. An application program that makesdecisions or solves problems in aparticular field, such as finance ormedicine, by using know ledge andanalytical rules defined by experts in thefield. It uses two components, a

know ledge base and an inference engine,to form conclusions. Additional toolsinclude user interfaces and explanationfacilities, which enable the system to justify or explain its conclusions as well asallow ing developers to run checks on theoperating system. See also artificialintelligence, inference engine, intelligentdatabase, encapsulation

n. In object-oriented programming, thepackaging of attributes (properties) and



functionality (methods or behaviors) to createan object that is essentially a black box —onewhose internal structure remains private and

whose services can be accessed by other objectsonly through messages passed via a clearlydefined interface (the programming equivalentof a mailbox or telephone line). Encapsulationensures that the object providing service canprevent other objects from manipulating its data

or procedures directly, and it enables the objectrequesting service to ignore the details of howthat service is provided. See also informationhiding.

black box

n. A unit of hardware or software whose internalstructure is unknown but whose function isdocumented. The internal mechanics of thefunction do not matter to a designer who uses ablack box to obtain that function. For example, amemory chip can be viewed as a black box.Many people use memory chips and designthem into computers, but generally onlymemory chip designers need to understand theirinternal operation.

encapsulate



vb. 1. To treat a collection of structuredinformation as a whole without affecting ortaking notice of its internal structure. In

communications, a message or packetconstructed according to one protocol, such as aTCP/IP packet, may be taken with its formattingdata as an undifferentiated stream of bits that isthen broken up and packaged according to alower-level protocol (for example, as ATM

packets) to be sent over a particular network; atthe destination, the lower-level packets areassembled, re-creating the message asformatted for the encapsulated protocol. See also ATM (definition 1). 2. In object-orientedprogramming, to keep the implementationdetails of a class a separate file whose contentsdo not need to be known by a programmerusing that class. See also object-orientedprogramming, TCP/IP.




sensor



sensor glove




transducer


energy.

virtual reality





information hiding





with each other or exchange information. 2.Software that enables a program to work withthe user (the user interface, which can be a



application programming interface

n. A set of routines used by an applicationprogram to direct the performance of procedures by the computer's operating system. Acronym: API. Also called application programinterface.

graphical user interface/ 15dec04






operating system

n. The software that controls the allocation andusage of hardware resources such as memory,central processing unit (CPU) time, disk space,and peripheral devices. The operating system isthe foundation software on which applicationsdepend. Popular operating systems includeWindows 98, Windows NT, Mac OS, and UNIX. Acronym: OS. Also called executive.



virtual



polymorphism










AT, IRQ

spam 1




spam 2




form of return spamming that can flood andpossibly disable the electronic mailbox of theoriginal spammer.

31dec05

filter

n. 1. A program or set of features within aprogram that reads its standard or designated

input, transforms the input in some desired way,and then writes the output to its standard ordesignated output destination. A database filter,for example, might flag information of a certainage. 2. In communications and electronics,hardware or software that selectively passescertain elements of a signal and eliminates or

minimizes others. A filter on a communicationsnetwork, for example, must be designed totransmit a certain frequency but attenuate(dampen) frequencies above it (a lowpass filter),those below it (a highpass filter), or those aboveand below it (a bandpass filter). 3. A pattern or

mask through which data is passed to weed outspecified items. For instance, a filter used in e-mail or in retrieving newsgroup messages canallow users to filter out messages from otherusers. See also e-mail filter, mask . 4. In






e-mail fi lter










pixel map



31dec05

BIOS





turned on. Although critical to performance, theBIOS is usually invisible to computer users. See also AMI BIOS, CMOS setup, Phoenix BIOS,ROM BIOS. Compare Toolbox.

flip-flop


multivibratorfloat








n. An arithmetic operation performed ondata stored in floating-point notation.Floating-point operations are usedwherever numbers may have either

fractional or irrational parts, as inspreadsheets and computer-aided design(CAD). Therefore, one measure of acomputer's power is how many m ill ions of floating-point operations per second(MFLOPS or megaflops) it can perform. Acronym: FLOP. Also called floating-pointoperation. See also floating-pointnotation, MFLOfloating-point notation

n. A numeric format that can be used torepresent very large real numbers and very



small real numbers. Floating-point numbers arestored in two parts, a mantissa and anexponent. The mantissa specifies the digits in

the number, and the exponent specifies themagnitude of the number (the position of thedecimal point). For example, the numbers314,600,000 and 0.0000451 are expressedrespectively as 3146E5 and 451E-7 in floating-point notation. Most microprocessors do not

directly support floating-point arithmetic;consequently, floating-point calculations areperformed either by using software or with aspecial floating-point processor. Also called exponential notation. See also fixed-pointnotation, floating-point processor, integer.


n. A numeric format in which the decimal pointhas a specified position. Fixed-point numbersare a compromise between integral formats,which are compact and efficient, and floating-point numeric formats, which have a greatrange of values. Like floating-point numbers,fixed-point numbers can have a fractional part,but operations on fixed-point numbers usually



take less time than floating-point operations.See also floating-point notation, integer.

integern. 1. A positive or negative "whole" number,such as 37, -50, or 764. 2. A data typerepresenting whole numbers. Calculationsinvolving only integers are much faster thancalculations involving floating-point numbers, so

integers are widely used in programming forcounting and numbering purposes. Integers canbe signed (positive or negative) or unsigned(positive). They can also be described as long orshort, depending on the number of bytesneeded to store them. Short integers, stored in

2 bytes, cover a smaller range of numbers (forexample, -32,768 through 32,767) than do longintegers (for example, -2,147,483,648 through2,147,483,647), which are stored in 4 bytes. Also called integral number. See also floating-point notation

byte

n. Short for b inary term. A unit of data, todayalmost always consisting of 8 bits. A byte canrepresent a single character, such as a letter, a



digit, or a punctuation mark. Because a byterepresents only a small amount of information,amounts of computer memory and storage are

usually given in kilobytes (1,024 bytes),megabytes (1,048,576 bytes), or gigabytes(1,073,741,824 bytes). Abbreviation: B. See also bit, gigabyte, kilobyte, megabyte. Compare octet, word.

character

n. A letter, number, punctuation mark, or othersymbol or control code that is represented to acomputer by one unit-1 byte-of information. A character is not necessarily visible, either on thescreen or on paper; a space, for example, is as

much a character as is the letter a or any of thedigits 0 through 9. Because computers mustmanage not only so-called printable charactersbut also the look (formatting) and transfer of electronically stored information, a character canadditionally indicate a carriage return or aparagraph mark in a word-processed document.It can be a signal to sound a beep, begin a newpage, or mark the end of a file. See also ASCII,control character, EBCDIC.

nibble or nybble



ASCII character set

n. A standard 7-bit code for representing ASCII

characters using binary values; code valuesrange from 0 to 127. Most PC-based systemsuse an 8-bit extended ASCII code, with an extra128 characters used to represent specialsymbols, foreign-language characters, andgraphic symbols. See also ASCII, character,EBCDIC, extended ASCII, standard ASCII.

extended ASCII

n. Any set of characters assigned to ASCIIvalues between decimal 128 and 255(hexadecimal 80 through FF). The specificcharacters assigned to the extended ASCII

codes vary between computers and betweenprograms, fonts, or graphics characters.Extended ASCII adds capability by allowing for128 additional characters, such as accentedletters, graphics characters, and specialsymbols. See also ASCII.

C++

n. An object-oriented version of the Cprogramming language, developed by Bjarne



Stroustrup in the early 1980s at BellLaboratories and adopted by a number of vendors, including Apple Computer and Sun



n. A programming paradigm in which a programis viewed as a collection of discrete objects that

are self-contained collections of data structuresand routines that interact with other objects. Acronym: OOP. See also C++, object (definition2), Objective-C.


n. A programming paradigm in which a programis viewed as a collection of discrete objects thatare self-contained collections of data structuresand routines that interact with other objects. Acronym: OOP. See also C++, object (definition2), Objective-C.

object

n. 1. Short for object code (machine-readablecode). 2. In object-oriented programming, avariable comprising both routines and data that



is treated as a discrete entity. See also abstractdata type, module (definition 1), object-orientedprogramming. 3. In graphics, a distinct entity.


module

n. 1. In programming, a collection of routinesand data structures that performs a particular

task or implements a particular abstract datatype. Modules usually consist of two parts: aninterface, which lists the constants, data types,variables, and routines that can be accessed byother modules or routines, and animplementation, which is private (accessible only

to the module) and which contains the sourcecode that actually implements the routines inthe module. See also abstract data type,information hiding, Modula-2, modularprogramming. 2. In hardware, a self-containedcomponent that can provide a complete functionto a system and can be interchanged with othermodules that provide similar functions. See also memory card, SIMM.

abstract data type



See also data type, object-orientedprogramming.

data typen. In programming, a definition of a set of datathat specifies the possible range of values of theset, the operations that can be performed onthe values, and the way in which the values arestored in memory. Defining the data type allows

a computer to manipulate the dataappropriately. Data types are most oftensupported in high-level languages and ofteninclude types such as real, integer, floatingpoint, character, Boolean, and pointer. How alanguage handles data typing is one of its major

characteristics. See also cast, constant,enumerated data type, strong typing, typechecking, user-defined data type, variable, weak typing.

toolbox

n. A set of predefined (and usually precompiled)routines a programmer can use in writing aprogram for a particular machine, environment,or application. Also called toolkit. See also library (definition 1).



Toolbox

n. A set of routines stored mostly in the read-

only memory of a Macintosh that providesapplication programmers with the tools neededto support the graphical interface characteristicof the computer. Also called User InterfaceToolbox.

disk drive

n. An electromechanical device that reads fromand writes to disks. The main components of adisk drive include a spindle on which the disk ismounted, a drive motor that spins the disk when

the drive is in operation, one or more read/writeheads, a second motor that positions theread/write head(s) over the disk, and controllercircuitry that synchronizes read/write activitiesand transfers information to and from thecomputer. Two types of disk drives are incommon use: floppy disk drives and hard disk drives. Floppy disk drives are designed to acceptremovable disks in either 5.25-inch or 3.5-inchformat; hard disk drives are faster, high-capacity



storage units that are completely enclosed in aprotective case.

paradigmn. An archetypal example or pattern thatprovides a model for a process or system

architecture

n. 1. The physical construction or design of a

computer system and its components. See also cache, CISC, closed architecture, network architecture, open architecture, pipelining, RISC.2. The data-handling capacity of amicroprocessor. 3. The design of applicationsoftware incorporating protocols and the means

for expansion and interfacing with otherprograms.

cache


quick access. A memory cache stores thecontents of frequently accessed RAM locationsand the addresses where these data items arestored. When the processor references anaddress in memory, the cache checks to see



intensity light source, such as a laser, andmirrors. Also called optical disc. 2. A technologythat forms the basis of media such as CD-ROM,

CD-ROM/XA, CD-I, CD-R, DVI, and PhotoCD.These media are all compact disc-based butstore various types of digital information andhave different read/write capabilities.Documentation for compact disc formats can befound in books designated by the color of their

covers. For example, documentation for audiocompact discs is found in the Red Book. See also CD-I, CD-R , CD-ROM, CD-ROM/XA , DVI,Green Book (definition 2), Orange Book (definition 2), PhotoCD, Red Book (definition 2).3. See CD.

disc


RS-232-C standard



n. An accepted industry standard for serialcommunications connections. Adopted by theElectrical Industries Association, this

Recommended Standard (RS) defines thespecific lines and signal characteristics used byserial communications controllers to standardizethe transmission of serial data between devices.The letter C denotes that the current version of the standard is the third in a series. See also

CTS, DSR , DTR , RTS, RXD, TXD.


n. Processing that involves the more or lesscontinuous participation of the user. Such acommand/response mode is characteristic of

microcomputers. Compare batch processing (definition 2).

interactive program




handshake

n. A series of signals acknowledging that

communication or the transfer of informationcan take place between computers or otherdevices. A hardware handshake is an exchangeof signals over specific wires (other than thedata wires), in which each device indicates itsreadiness to send or receive data. A softwarehandshake consists of signals transmitted overthe same wires used to transfer data, as inmodem-to-modem communications overtelephone lines.

31dec05

1jan2006

spam 1


cases, the content of a spam message or articleis not relevant to the topic of the newsgroup orthe interests of the recipient; spam is an abuseof the Internet in order to distribute a message



(usually commercial or religious) to a hugenumber of people at minimal cost.

spam2

vb. To distribute unwanted, unrequested mailwidely on the Internet by posting a message totoo many recipients or too many newsgroups.The act of distributing such mail, known asspamming, angers most Internet users and has

been known to invite retaliation, often in theform of return spamming that can flood andpossibly disable the electronic mailbox of theoriginal spammer

6jan06

ADSL

n. Acronym for asymmetric digital subscriberline. Technology and equipment allowing high-speed digital communication, including videosignals, across an ordinary twisted-pair copperphone line, with speeds up to 8 Mbps

(megabits per second) downstream (tothe customer) and up to 640 Kbps (kilobitsper second) upstream. ADSL access to theInternet is offered by some regional telephone



companies, offering users faster connectiontimes than those available through connectionsmade over standard phone lines. Also called

asymmetric digital subscriber loop. Compare SDSL.

SDSL

n. Acronym for symmetric (or s ingle-line) d igitalsubscriber l ine, a digital telecommunications

technology that is a variation of HDSL. SDSLuses one pair of copper wire rather than twopairs of wires and transmits at 1.544 Mbps.Compare ADSL.

VoIP

n. Acronym for Voice over IP. The use of theInternet Protocol (IP) for transmitting voicecommunications. VoIP delivers digitized audio inpacket form and can be used for transmittingover intranets, extranets, and the Internet. It isessentially an inexpensive alternative totraditional telephone communication over thecircuit-switched Public Switched TelephoneNetwork (PSTN). VoIP covers computer-to-computer, computer-to-telephone, andtelephone-based communications. For the sake



of compatibility and interoperability, a groupcalled the VoIP Forum promotes productdevelopment based on the ITU-T H.323

standard for transmission of multimedia over theInternet. Also called Internet telephony. See also H.323.

volati le memory

n. 1. Memory, such as RAM, that loses its data

when the power is shut off. Compare nonvolatilememory. 2. Memory used by a program that canchange independently of the program, such asmemory shared by another program or by aninterrupt service routine.

nonvolatile memory

n. A storage system that does not lose datawhen power is removed from it. Intended torefer to core memory, ROM, EPROM, flashmemory, bubble memory, or battery-backedCMOS RAM, the term is occasionally used inreference to disk subsystems as well. See also bubble memory, CMOS RAM, core, EPROM, flashmemory, ROM.

flash memory



n. A type of nonvolatile memory. Flash memoryis similar to EEPROM memory in function but itmust be erased in blocks, whereas EEPROM can

be erased one byte at a time. Because of itsblock-oriented nature, flash memory iscommonly used as a supplement to orreplacement for hard disks in portablecomputers. In this context, flash memory eitheris built into the unit or, more commonly, is

available as a PC Card that can be plugged intoa PCMCIA slot. A disadvantage of the block-oriented nature of flash memory is that it cannotbe practically used as main memory (RAM)because a computer needs to be able to write tomemory in single-byte increments. See also EEPROM, nonvolatile memory, PC Card, PCMCIA slot

IP

n. Acronym for Internet Protocol. The protocolwithin TCP/IP that governs the breakup of datamessages into packets, the routing of thepackets from sender to destination network andstation, and the reassembly of the packets intothe original data messages at the destination. IPruns at the internetwork layer in the TCP/IP



sometimes error-control data. See also packetswitching.

USBn. Acronym for universal serial bus. A serial buswith a data transfer rate of 12 megabits persecond (Mbps) for connecting peripherals to amicrocomputer. USB can connect up to 127peripherals, such as external CD-ROM drives,

printers, modems, mice, and keyboards, to thesystem through a single, general-purpose port.This is accomplished by daisy chainingperipherals together. USB is designed to supportthe ability to automatically add and configurenew devices and the ability to add such devices

without having to shut down and restart thesystem (hot plugging). USB was developed byIntel, Compaq, DEC, IBM, Microsoft, NEC, andNorthern Telecom. It competes with DEC's

ACCESS.bus for lower-speed applications. See also bus, daisy chain, hot plugging, input/outputport, peripheral. Compare ACCESS.bus.


n. The design of the bus in IBM PS/2 computers(except Models 25 and 30). The Micro Channel



is electrically and physically incompatible withthe IBM PC/AT bus. Unlike the PC/AT bus, theMicro Channel functions as either a 16-bit or a

32-bit bus. The Micro Channel also can bedriven independently by multiple bus masterprocessors.

PS/ 2 bus


bus

n. A set of hardware lines (conductors) used fordata transfer among the components of acomputer system. A bus is essentially a sharedhighway that connects different parts of the

system-including the processor, disk-drivecontroller, memory, and input/output ports-andenables them to transfer information. The busconsists of specialized groups of lines that carrydifferent types of information. One group of lines carries data; another carries memoryaddresses (locations) where data items are to befound; yet another carries control signals. Busesare characterized by the number of bits they cantransfer at a single time, equivalent to thenumber of wires within the bus. A computer



with a 32-bit address bus and a 16-bit data bus,for example, can transfer 16 bits of data at atime from any of 232 memory locations. Most

PCs contain one or more expansion slots intowhich additional boards can be plugged toconnect them to the bus.

hard disk

n. A device containing one or more inflexible

platters coated with material in which data canbe recorded magnetically, together with theirread/write heads, the head-positioningmechanism, and the spindle motor in a sealedcase that protects against outside contaminants.The protected environment allows the head to

fly 10 to 25 millionths of an inch above thesurface of a platter rotating typically at 3,600 to7,200 rpm; therefore, much more data can bestored and accessed much more quickly than ona floppy disk. Most hard disks contain from twoto eight platters. Also called hard disk drive.Compare floppy disk .

soft copy




hard copy

n. Printed output on paper, film, or other

permanent medium. Compare soft copy.URL

n. Acronym for Uniform R esource Locator. Anaddress for a resource on the Internet. URLs areused by Web browsers to locate Internet

resources. A URL specifies the protocol to beused in accessing the resource (such as http: fora World Wide Web page or ftp: for an FTP site),the name of the server on which the resourceresides (such as //www.whitehouse.gov), and,optionally, the path to a resource (such as anHTML document or a file on that server). See


HDSL

n. Acronym for H igh-bit-rate D igital Subscriber

L ine. A form of DSL, HDSL is a protocol fordigital transmission of data over standardcopper telecommunications lines (as opposed tofiber-optic lines) at rates of 1.544 Mbps in both



n. A thin strand of transparent material used tocarry optical signals. Optical fibers areconstructed from special kinds of glass and

plastic, and they are designed so that a beam of light introduced at one end will remain withinthe fiber, reflecting off the inner surfaces as ittravels down the length of the fiber. Opticalfibers are inexpensive, compact, and lightweightand are often packaged many hundred to a

single cable. See also fiber optics.

optical mouse

n. A type of mouse that uses a pair of light-emitting diodes (LEDs) and a special reflectivegrid pad to detect motion. The two lights are of

different colors, and the special mouse pad hasa grid of lines in the same colors, one color forvertical lines and another for horizontal lines.Light detectors paired with the LEDs sense whena colored light passes over a line of the samecolor, indicating the direction of movement. See also mouse. Compare mechanical mouse,optomechanical mouse.

fiber optics



n. A technology for the transmission of lightbeams along optical fibers. A light beam, suchas that produced in a laser, can be modulated to

carry information. Because light has a higherfrequency on the electromagnetic spectrum thanother types of radiation, such as radio waves, asingle fiber-optic channel can carry significantlymore information than most other means of information transmission. Optical fibers are thin

strands of glass or other transparent material,with dozens or hundreds of strands housed in asingle cable. Optical fibers are essentiallyimmune to electromagnetic interference. See also optical fiber.

mechanical mouse

n. A type of mouse in which the motion of a ballon the bottom of the mouse is translated intodirectional signals. As the user moves themouse, the ball rolls, turning a pair of wheelsmounted at right angles inside the mouse thathave conductive markings on their surfaces.Because the markings permit an electric currentto flow, a set of conductive brushes that ride onthe surface of the conductive wheels can detectthese conductive markings. The electronics in



the mouse translate these electrical movementsignals into mouse-movement information thatcan be used by the computer. See also mouse,

trackball. Compare optical mouse,optomechanical mouse.

voice recognition

n. The capability of a computer to understandthe spoken word for the purpose of receiving

commands and data input from the speaker.Systems that can recognize limited vocabulariesas spoken by specific individuals have beendeveloped, but developing a system that dealswith a variety of speech patterns and accents,as well as with the various ways in which a

request or a statement can be made, is moredifficult, although advances are being made inthis area. Also called speech recognition. See also artificial intelligence, dictation software,neural network .

neural network

n. A type of artificial-intelligence systemmodeled after the neurons (nerve cells) in abiological nervous system and intended tosimulate the way a brain processes information,



learns, and remembers. A neural network isdesigned as an interconnected system of processing elements, each with a limited

number of inputs and an output. Theseprocessing elements are able to "learn" byreceiving weighted inputs that, with adjustment,time, and repetition, can be made to produceappropriate outputs. Neural networks are usedin areas such as pattern recognition, speech

analysis, and speech synthesis. See also artificialintelligence, pattern recognition (definition 1).

pattern recognition

n. 1. A broad technology describing the ability of a computer to identify patterns. The term

usually refers to computer recognition of visualimages or sound patterns that have beenconverted to arrays of numbers. 2. Therecognition of purely mathematical or textualpatterns.

thumbnail

n. A miniature version of an image or electronicversion of a page that is generally used to allowquick browsing through multiple images orpages. For example, Web pages often contain



thumbnails of images (which can be loadedmuch more quickly by the Web browser than thefull-size image). Many of these thumbnails can

be clicked on to load the complete version of theimage

25jan06wednes

ADSL

n. Acronym for asymmetric digital subscriberline. Technology and equipment allowing high-speed digital communication, including videosignals, across an ordinary twisted-pair copperphone line, with speeds up to 8 Mbps (megabitsper second) downstream (to the customer) andup to 640 Kbps (kilobits per second) upstream.

ADSL access to the Internet is offered by someregional telephone companies, offering usersfaster connection times than those availablethrough connections made over standard phonelines. Also called asymmetric digital subscriberloop. Compare SDSL.


n. A protocol for servers on the Internet thatreceive, store, and transmit e-mail and for



user returns to the same Web site, the browsersends a copy of the cookie back to the server.Cookies are used to identify users, to instruct

the server to send a customized version of therequested Web page, to submit accountinformation for the user, and for otheradministrative purposes. 3. Originally an allusionto fortune cookie, a UNIX program that outputsa different message, or "fortune", each time it is

used. On some systems, the cookie program isrun during user logon.

cache


quick access. A memory cache stores thecontents of frequently accessed RAM locationsand the addresses where these data items arestored. When the processor references anaddress in memory, the cache checks to seewhether it holds that address. If it does hold theaddress, the data is returned to the processor; if it does not, a regular memory access occurs. A cache is useful when RAM accesses are slowcompared with the microprocessor speed,because cache memory is always faster than



main RAM memory. See also disk cache, waitstate.

benchmark 1

n. A test used to measure hardware or softwareperformance. Benchmarks for hardware useprograms that test the capabilities of theequipment-for example, the speed at which aCPU can execute instructions or handle floating-

point numbers. Benchmarks for softwaredetermine the efficiency, accuracy, or speed of aprogram in performing a particular task, such asrecalculating data in a spreadsheet. The samedata is used with each program tested, so theresulting scores can be compared to see which

programs perform well and in what areas. Thedesign of fair benchmarks is something of anart, because various combinations of hardwareand software can exhibit widely variableperformance under different conditions. Often,after a benchmark has become a standard,developers try to optimize a product to run thatbenchmark faster than similar products run it inorder to enhance sales. See also sieve of Eratosthenes.

benchmark 2




benign virusn. A program that exhibits properties of a virus,such as self-replication, but does not otherwisedo harm to the computer systems that it infects.

2feb06

thumbnail

n. A miniature version of an image or electronicversion of a page that is generally used to allowquick browsing through multiple images orpages. For example, Web pages often containthumbnails of images (which can be loadedmuch more quickly by the Web browser than thefull-size image). Many of these thumbnails canbe clicked on to load the complete version of theimage.

MP3

n. Acronym for MPEG Audio Layer-3. A digitalaudio coding scheme used in distributingrecorded music over the Internet. MP3 shrinksthe size of an audio file by a factor of 10 to 12



without seriously degrading the quality (CD-recording level) of the sound. MP3 files aregiven the file extension .mp3. Although MP3 is

part of the MPEG family, it is audio-only and isnot the same as the now-defunct MPEG-3standard

string

n. A data structure composed of a sequence of

characters usually representing human-readabletext.

array

n. In programming, a list of data values, all of the same type, any element of which can be

referenced by an expression consisting of thearray name followed by an indexing expression.

Arrays are part of the fundamentals of datastructures, which, in turn, are a majorfundamental of computer programming. See

also array element, index, record1, vector.

vector

n. 1. In mathematics and physics, a variablethat has both distance and direction. Compare scalar. 2. In computer graphics, a line drawn in



grid

n. 1. Two sets of lines or linear elements at right

angles to each other. 2. A spreadsheet is a gridof rows and columns; a graphics screen is a gridof horizontal and vertical lines of pixels. 3. Inoptical character recognition, a grid is used formeasuring or specifying characters. See also Cartesian coordinates.

data stream

n. An undifferentiated, byte-by-byte flow of data.

data structure

n. An organizational scheme, such as a record orarray, that can be applied to data to facilitateinterpreting the data or performing operationson it.

byte

n. Short for b inary term. A unit of data, today

almost always consisting of 8 bits. A byte canrepresent a single character, such as a letter, adigit, or a punctuation mark. Because a byterepresents only a small amount of information,



amounts of computer memory and storage areusually given in kilobytes (1,024 bytes),megabytes (1,048,576 bytes), or gigabytes

(1,073,741,824 bytes). Abbreviation: B. See also bit, gigabyte, kilobyte, megabyte. Compare octet, word.

character

n. A letter, number, punctuation mark, or other

symbol or control code that is represented to acomputer by one unit-1 byte-of information. A character is not necessarily visible, either on thescreen or on paper; a space, for example, is asmuch a character as is the letter a or any of thedigits 0 through 9. Because computers must

manage not only so-called printable charactersbut also the look (formatting) and transfer of electronically stored information, a character canadditionally indicate a carriage return or aparagraph mark in a word-processed document.It can be a signal to sound a beep, begin a newpage, or mark the end of a file. See also ASCII,control character, EBCDIC.

assembly language



n. A low-level programming language usingabbreviations or mnemonic codes in which eachstatement corresponds to a single machine

instruction. An assembly language is translatedto machine language by the assembler and isspecific to a given processor. Advantages of using an assembly language include increasedexecution speed and direct programmerinteraction with system hardware. See also

assembler, compiler, high-level language, low-level language, machine code.

assembler

n. A program that converts assembly languageprograms, which are understandable by

humans, into executable machine language. See also assemble, assembly language, assemblylisting, compiler (definition 2), machine code.

compiler

n. 1. Any program that transforms one set of symbols into another by following a set of syntactic and semantic rules. 2. A program thattranslates all the source code of a programwritten in a high-level language into object codeprior to execution of the program. See also



assembler, compile, high-level language,interpreted language, language processor,object code.

high-level language

n. A computer language that provides a level of abstraction from the underlying machinelanguage. Statements in a high-level languagegenerally use keywords similar to English and

translate into more than one machine-languageinstruction. In practice, every computerlanguage above assembly language is a high-level language. Acronym: HLL. Also called high-order language. Compare assembly language.

machine code

n. The ultimate result of the compilation of assembly language or any high-level languagesuch as C or Pascal: sequences of 1s and 0s thatare loaded and executed by a microprocessor.Machine code is the only language computersunderstand; all other programming languagesrepresent ways of structuring human languageso that humans can get computers to performspecific tasks. Also called machine language.See also compiler (definition 2).



stored in two parts, a mantissa and anexponent. The mantissa specifies the digits inthe number, and the exponent specifies the

magnitude of the number (the position of thedecimal point). For example, the numbers314,600,000 and 0.0000451 are expressedrespectively as 3146E5 and 451E-7 in floating-point notation. Most microprocessors do notdirectly support floating-point arithmetic;

consequently, floating-point calculations areperformed either by using software or with aspecial floating-point processor. Also called exponential notation. See also fixed-pointnotation, floating-point processor, integer.


n. A number represented by a mantissa and anexponent according to a given base. Themantissa is usually a value between 0 and 1. Tofind the value of a floating-point number, thebase is raised to the power of the exponent, andthe mantissa is multiplied by the result. Ordinaryscientific notation uses floating-point numberswith 10 as the base. In a computer, the base forfloating-point numbers is usually 2.




n. An arithmetic operation performed on datastored in floating-point notation. Floating-pointoperations are used wherever numbers may

have either fractional or irrational parts, as inspreadsheets and computer-aided design (CAD).Therefore, one measure of a computer's poweris how many millions of floating-point operationsper second (MFLOPS or megaflops) it canperform. Acronym: FLOP. Also called floating-

point operation. See also floating-point notation,MFLOPS.

integer

n. 1. A positive or negative "whole" number,such as 37, -50, or 764. 2. A data type

representing whole numbers. Calculationsinvolving only integers are much faster thancalculations involving floating-point numbers, sointegers are widely used in programming forcounting and numbering purposes. Integers canbe signed (positive or negative) or unsigned(positive). They can also be described as long orshort, depending on the number of bytesneeded to store them. Short integers, stored in2 bytes, cover a smaller range of numbers (forexample, -32,768 through 32,767) than do long



integers (for example, -2,147,483,648 through2,147,483,647), which are stored in 4 bytes. Also called integral number. See also floating-

point notatio



.



PU cachen. A section of fast memory linking the CPU(central processing unit) and main memory thattemporarily stores data and instructions the CPUneeds to execute upcoming commands andprograms. Considerably faster than main

memory, the CPU cache contains data that istransferred in blocks, thereby speedingexecution. The system anticipates the data it willneed through algorithms. Also called cache



memory, memory cache. See also cache, CPU, VCACHE.

CPUn. Acronym for central processing unit. Thecomputational and control unit of a computer.The CPU is the device that interprets andexecutes instructions. Mainframes and earlyminicomputers contained circuit boards full of

integrated circuits that implemented the CPU.Single-chip central processing units, calledmicroprocessors, made possible personalcomputers and workstations. Examples of single-chip CPUs are the Motorola 68000, 68020,and 68030 chips and the Intel 8080, 8086,

80286, 80386, and i486 chips. The CPU-ormicroprocessor, in the case of a microcomputer-has the ability to fetch, decode, and executeinstructions and to transfer information to andfrom other resources over the computer's maindata-transfer path, the bus. By definition, theCPU is the chip that functions as the "brain" of acomputer. In some instances, however, the termencompasses both the processor and thecomputer's memory or, even more broadly, the




aqmifrS kay;aom jA l&dkrsm;udkoD;jcm;wm0efcGJ a0owfrSwfay;jcif;/



n. The assignment of tasks to independent

contractors, such as individual consultants orservice bureaus. Tasks such as data entry andprogramming are often performed viaoutsourcing.

FromOtherFileSunday, February 17, 2008t0254 þ

t0169 u© t0190 *¾

t0237 í

t0246 pö250 uú

spam(n) (vb) pyrf;WYSBYGI(adj) 0wfpfbD*sD

irewall(n) zkd if; &m; a0gvf

packet(n) yufuuf



communications protocol(n) qufoG,fa&; y&dkwdkaum

SMPT)Simple Mail Transfer Protocol(n) &dk;&Sif;aomar;vfx&efpzm; y&dkwdkaum

snail mail (n) yufusdar;vf

hroughput(n) o&l;yGwf

black box(n) bl;euf

0outsourcing(n)

6POP(Post Office Protocol) pmwdkuf y&dkwdkaum




Friday, November 23, 2007

,ae.urÇmMuD;wGifuRef awmfwdk.onfuGefjy lwma0g[m&rsm;ESif.eyef;owf ae

& ayjyD/ uGefjy lwma0g[m&rsm;wae.wjcm; arG;zGm; vm ae&m jzpfay:wdk;wufrS

kwdk.udkem;v,foabmayguf&efteJ H k;vdktyfcsufrSmtajccHtus H k;j pfonf.

a0g[m&rsm;

\taMumif; aoaojcmjcma&a&&m&modbdk.vdktyfygw,f/



vloHk;rsm;aom tifwmeufESif.uGefjy lwma0g[m&rsm;bmomjyef/

10outsourcing atmuf if;

outsourcing jyifytzGJ.eJ.yl;aygif; aqmif&Gufjcif;/


a mifrS kay;aom j l&dkrsm;udkoD;jcm;wm0efcGJ a0owfrSwfay;jcif;/


atmuf if;rSw if.jy kvkyfav.&dSw,f/

n. The assignment of tasks to independent

contractors, such as individual consultants orservice bureaus. Tasks such as data entry andprogramming are often performed viaoutsourcing.



11run time

n. 1. The time period during which a program isrunning. See also compile time, dynamicallocation, dynamic binding, link time. 2. Theamount of time needed to execute a givenprogram.

12run-time error

n. A software error that occurs while a program

is being executed, as detected by a compiler or other supervisory program.

1spam(n)

An unsolicited e-mail message sent to manyrecipients at one time, or a news article postedsimultaneously to many newsgroups. Spam is

the electronic equivalent of junk mail. In mostcases, the content of a spam message or articleis not relevant to the topic of the newsgroup orthe interests of the recipient; spam is an abuseof the Internet in order to distribute a message



(usually commercial or religious) to a hugenumber of people at minimal cost.

spam(vb)To distribute unwanted, unrequested mail

widely on the Internet by posting a message totoo many recipients or too many newsgroups.The act of distributing such mail, known asspamming, angers most Internet users and has

been known to invite retaliation, often in theform of return spamming that can flood andpossibly disable the electronic system.

1spam(n) (vb) pyrf;

awmiff;cH

rSm,ljcif;r&dSbJydk.aomtDar;vfpmrsm;/



y.dk vdkufaom

owif;tcsuftvufrsm;?aqmif;yg;rsm;onfvufcH&&dSaomoleJ.rouf qdkifaomt&mrsm;jzpfaewwfonf/Oyrm vltcGif.ta&;umuG,fapmif.a&Smufjcif;ESif.ywfoufaomowif;tcsuf

tvufrsm;udk vuf,mtpGef;a&muf̂ vljz ltpGef;a&muftzGJ.tpnf;rsm;



(ku klus kan)/

vljzltpGef;a&muftzGJ.tpnf;rsm;ponfwdk.odk.odk.ay;ydk.jcif;/

xdkuJ.odk.rrSmMum;bJay;ojzif.vufcH&&dSolrsm;\ar;vfabmufpfrsm;

wGiftrdS kufozG,fjzpfaewwfonf/


jzpfygonf/

2WYSBYGI

adj. Acronym for What You See Before You GetIt. Providing a preview of the effects of thechanges the user has selected before the

changes are finally applied. For example, adialog box in a word processing program mightdisplay a sample of the font a user has chosenbefore the font is actually changed in thedocument. The user can cancel any changesafter previewing them, and the document will beunaffec ted. See also WYSIWYG.

2 WYSBYGI(adj) 0wfpfbD*sD

What You See Before You Get It



rdrd \a&;om;aom ( documents ) rsm;\ zGef. (font) t&G,f?umvmponf wdk.udkSk Mud kwifMunf.&S k jy kjyifEdS

kifaom?aomjrifuGif;/

3firewall

n. A security system intended to protect anorganization's network against external threats,

such as hackers, coming from another network,such as the Internet. Usually a combination of hardware and software, a firewall preventscomputers in the organization's network fromcommunicating directly with computers externalto the network and vice versa. Instead, allcommunication is routed through a proxy serveroutside of the organization's network, and theproxy server decides whether it is safe to let aparticular message or file pass through to theorganization's network. See also proxy server.

3firewall(n) zkd if; &m; a0gvf

tifwmeufpaomjyifyuGef,ufwckckrSjcdrf;ajcmufrKS krsm;udkumuG,f&efwnfaqmufxm;aom vHkjcH ka&;tzGJ.tpnf;jzpfonf/[wf0Jaqm.0J(2)ckvHk;yg0ifonf/




uGefjy lwmrsm;udk

jyifyuGef,ufESif.wdkuf&dkufqufoG,fír&&efjzwfawmufwm;jrpfxm;o

nf/

qufoG,frS ktm;vHk;udk ya&mfqDqm.Am; (proxy server) rSwqif.

jy kvkyf&onf/



4packet

n. 1. A unit of information transmitted as awhole from one device to another on a network.2. In packet-switching networks, a transmission

unit of fixed maximum size that consists of binary digits representing both data and aheader containing an identification number,source and destination addresses, andsometimes error-control data. See also packetswitching.

packet switching

n. A message-delivery technique in which smallunits of information (packets) are relayedthrough stations in a computer network along



the best route available between the source andthe destination. A packet-switching network handles information in small units, breaking long

messages into multiple packets before routing. Although each packet may travel along adifferent path, and the packets composing amessage may arrive at different times or out of sequence, the receiving computer reassemblesthe original message correctly. Packet-switching

networks are considered to be fast and efficient.To manage the tasks of routing traffic andassembling/disassembling packets, such anetwork requires some intelligence from thecomputers and software that control delivery.The Internet is an example of a packet-switching network. Standards for packetswitching on networks are documented in the -ITU recommendation X.25. Compare circuitswitching

4packet(n) yufuuf






(header) rsm;? ay;ydk.aomu&d,m\vdyfpm

vufcHrnf.u&d,m\vdyfpm? trSm;xdef; owif;tcsuftvufrsm; (

error-control data ) rsm;jzif.zGJ.pnf;xm;ygonf/


uGefjy lwmwckESif.wckcsdwfquf&efESif.owif;tcsuftvufrsm;



oG,f Edkifrnf/

trsm;vufcHaomy&dkwdkaumwGifaqmzf0J [wf0J(7)vTm pkjzif.zGJ.pnf;

xm;ygonf/

n. A set of rules or standards designed to enablecomputers to connect with one another and toexchange information with as little error aspossible. The protocol generally accepted forstandardizing overall computer communicationsis a seven-layer set of hardware and softwareguidelines known as the OSI (Open SystemsInterconnection) model. A somewhat differentstandard, widely used before the OSI model wasdeveloped, is IBM's SNA (Systems Network



Architecture). The word protocol is often used,sometimes confusingly, in reference to amultitude of standards affecting different

aspects of communication, such as file transfer(for example, XMODEM and ZMODEM),handshaking (for example, XON/XOFF), andnetwork transmissions (for example, CSMA/CD).See also ISO/OSI model, SNA .

6(SMPT)Simple Mail Transfer Protocol (n)



jy kygonf/

n. A TCP/IP protocol for sending messages fromone computer to another on a network. Thisprotocol is used on the Internet to route e-mail.

Acronym: SMTP. See also communicationsprotocol, TCP/IP. Compare CCITT X series, Post

Office Protocol.7snail mail

n. A popular phrase on the Internet for referringto mail services provided by the U.S. Postal



Service and similar agencies in other countries.The term has its origins in the fact that regularpostal mail is slow compared with e-mail.

7snail mail yufusdar;vf tifwmeufay:wGifor&kd;us

^&kd;&dk;pmwdkuf rSydk.aomar;vf0efaqmifrS kudk&nf nTef;ajymqdkaompum;&yfjzpfonf/

tD;ar;vfESif.EdS kif;,SOfvQifor&kd;us ^&kd;&dk;pmwdkuf rSydk.aomar;vf0efaqmifrS konftvGefaES;auG;onfudk&nf

nTef;ajymqdkaompum;&yfjzpfonf/&dk;&dk;ar;vfudkysuf&,fjy kaom



n. 1. The data transfer rate of a network,

measured as the number of bits per secondtransmitted. 2. A measure of the dataprocessing rate in a computer system.











9black box

n. A unit of hardware or software whose internalstructure is unknown but whose function isdocumented. The internal mechanics of the

function do not matter to a designer who uses ablack box to obtain that function. For example, amemory chip can be viewed as a black box.Many people use memory chips and designthem into computers, but generally onlymemory chip designers need to understand their

internal operation.

9black box bl;euf



udkod,HkrQjzif.designer

onfol.design

wGifxnf.oGif;toHk; jy kEdkifygw,f/Oyrm tm;jzif. memory chip udk





twGif;tao;pdwfzGJ.pnf;yHk tvkyfvkyf aqmifyHk function udkem;v,foabmayguf7efwm0ef,l&ygw,f/


n. An Intel chip that handles interrupt requests(IRQs). IBM AT machines use twoprogrammable interrupt controllers toaccommodate a maximum of 15 IRQs. The

programmable interrupt controller has beenreplaced by the advanced programmableinterrupt controller (APIC), which supportsmultiprocessing. Acronym: PIC. See also IBM

AT, IRQ.

circuit switching

n. A method of opening communications lines,as through the telephone system, by creating a



physical link between the initiating and receivingparties. In circuit switching, the connection ismade at a switching center, which physically

connects the two parties and maintains an openline between them for as long as needed. Circuitswitching is typically used on the dial-uptelephone network, and it is also used on asmaller scale in privately maintainedcommunications networks. Unlike other methods

of transmission, such as packet switching, itrequires the link to be established before anycommunication can take place. Comparemessage switching, packet switching

WYSIWYGmarkup language

n. A set of codes in a text file that instruct acomputer how to format it on a printer or videodisplay or how to index and link its contents.Examples of markup languages are HypertextMarkup Language (HTML) and ExtensibleMarkup Language (XML), which are used in Webpages, and Standard Generalized MarkupLanguage (SGML), which is used for typesetting



and desktop publishing purposes and inelectronic documents. Markup languages of thissort are designed to enable documents and

other files to be platform-independent andhighly portable between applications. See alsoHTML, SGML, XML.

interface

n. 1. The point at which a connection is made

between two elements so that they can work with each other or exchange information. 2.Software that enables a program to work withthe user (the user interface, which can be acommand-line interface, menu-driven, or agraphical user interface), with another program

such as the operating system, or with thecomputer's hardware. See also applicationprogramming interface, graphical user interface.3. A card, plug, or other device that connectspieces of hardware with the computer so thatinformation can be moved from place to place.For example, standardized interfaces such asRS-232-C standard and SCSI enablecommunications between computers andprinters or disks. See also RS-232-C standard,SCSI.



.pdf

n. The file extension that identifies documents

encoded in the Portable Document Formatdeveloped by Adobe Systems. In order todisplay or print a .pdf file, the user should obtainthe freeware Adobe Acrobat Reader. See also

Acrobat, Portable Document Format

Portable Document Format

n. The Adobe specification for electronicdocuments that use the Adobe Acrobat family of servers and readers. Acronym: PDF. See also

Acrobat, .pdf .

portable language

n. A language that runs in the same way ondifferent systems and therefore can be used fordeveloping software for all of them. C,FORTRAN, and Ada are portable languagesbecause their implementations on differentsystems are highly uniform; assembly language

is extremely nonportable.




n. Memory access that does not involve themicroprocessor and is frequently used for datatransfer directly between memory and an


n. An object-oriented version of the Cprogramming language, developed by BjarneStroustrup in the early 1980s at BellLaboratories and adopted by a number of vendors, including Apple Computer and SunMicrosystems, Inc. See also C, Objective-C,object-oriented programming.



n. In programming, a data set defined by theprogrammer in terms of the information it cancontain and the operations that can beperformed with it. An abstract data type is moregeneralized than a data type constrained by theproperties of the objects it contains-for example,the data type "pet" is more generalized than thedata types "pet dog," "pet bird," and "pet fish."The standard example used in illustrating anabstract data type is the stack", a small portion



of memory used to store information, generallyon a temporary basis. As an abstract data type,the stack is simply a structure onto which values

can be pushed (added) and from which they canbe popped (removed). The type of value, suchas integer, is irrelevant to the definition.

The way in which the program performsoperations on abstract data types isencapsulated, or hidden, from the rest of theprogram. Encapsulation enables theprogrammer to change the definition of the datatype or its operations without introducing errorsto the existing code that uses the abstract datatype. Abstract data types represent anintermediate step between traditional

programming and object-oriented programming.See also data type, object-orientedprogramming.

encapsulation

n. In object-oriented programming, the

packaging of attributes (properties) andfunctionality (methods or behaviors) to createan object that is essentially a black box —onewhose internal structure remains private andwhose services can be accessed by other objects



only through messages passed via a clearlydefined interface (the programming equivalentof a mailbox or telephone line). Encapsulation


fuzzy logic

n. A form of logic used in some expert systemsand other artificial-intelligence applications inwhich variables can have degrees of truthfulnessor falsehood represented by a range of values

between 1 (true) and 0 (false). With fuzzy logic,the outcome of an operation can be expressedas a probability rather than as a certainty. Forexample, an outcome might be probably true,possibly true, possibly false, or probably false.See also expert system.

expert system

n. An application program that makes decisionsor solves problems in a particular field, such asfinance or medicine, by using knowledge and



analytical rules defined by experts in the field. Ituses two components, a knowledge base and aninference engine, to form conclusions. Additional

tools include user interfaces and explanationfacilities, which enable the system to justify orexplain its conclusions as well as allowingdevelopers to run checks on the operatingsystem. See also artificial intelligence, inferenceengine, intelligent database, encapsulation

n. In object-oriented programming, thepackaging of attributes (properties) andfunctionality (methods or behaviors) to createan object that is essentially a black box —onewhose internal structure remains private andwhose services can be accessed by other objects

only through messages passed via a clearlydefined interface (the programming equivalentof a mailbox or telephone line). Encapsulationensures that the object providing service canprevent other objects from manipulating its dataor procedures directly, and it enables the object


encapsulate




sensor



sensor glove




transducer


energy.

virtual reality





information hiding





subroutine to be changed without breaking theroutines that use it. See also break , module,routine, subroutine.

module

n. 1. In programming, a collection of routinesand data structures that performs a particulartask or implements a particular abstract datatype. Modules usually consist of two parts: an

interface, which lists the constants, data types,variables, and routines that can be accessed byother modules or routines, and animplementation, which is private (accessible onlyto the module) and which contains the sourcecode that actually implements the routines in

the module. See also abstract data type,information hiding, Modula-2, modularprogramming. 2. In hardware, a self-containedcomponent that can provide a complete functionto a system and can be interchanged with othermodules that provide similar functions. See alsomemory card, SIMM.

interface

n. 1. The point at which a connection is madebetween two elements so that they can work







n. A set of routines used by an applicationprogram to direct the performance of procedures by the computer's operating system.

Acronym: API. Also called application programinterface.




virtual



polymorphism










AT, IRQ

spam1




spam2





31dec05

filter










e-mail filter










pixel map



31dec05

BIOS







n. An arithmetic operation performed on datastored in floating-point notation. Floating-pointoperations are used wherever numbers mayhave either fractional or irrational parts, as in

spreadsheets and computer-aided design (CAD).Therefore, one measure of a computer's poweris how many millions of floating-point operationsper second (MFLOPS or megaflops) it canperform. Acronym: FLOP. Also called floating-point operation. See also floating-point notation,MFLOfloating-point notation

n. A numeric format that can be used torepresent very large real numbers and verysmall real numbers. Floating-point numbers arestored in two parts, a mantissa and an



exponent. The mantissa specifies the digits inthe number, and the exponent specifies themagnitude of the number (the position of the

decimal point). For example, the numbers314,600,000 and 0.0000451 are expressedrespectively as 3146E5 and 451E-7 in floating-point notation. Most microprocessors do notdirectly support floating-point arithmetic;consequently, floating-point calculations are

performed either by using software or with aspecial floating-point processor. Also calledexponential notation. See also fixed-pointnotation, floating-point processor, integer.


n. A numeric format in which the decimal pointhas a specified position. Fixed-point numbersare a compromise between integral formats,which are compact and efficient, and floating-point numeric formats, which have a greatrange of values. Like floating-point numbers,fixed-point numbers can have a fractional part,but operations on fixed-point numbers usuallytake less time than floating-point operations.See also floating-point notation, integer.

integer



n. 1. A positive or negative "whole" number,such as 37, -50, or 764. 2. A data typerepresenting whole numbers. Calculations

involving only integers are much faster thancalculations involving floating-point numbers, sointegers are widely used in programming forcounting and numbering purposes. Integers canbe signed (positive or negative) or unsigned(positive). They can also be described as long or

short, depending on the number of bytesneeded to store them. Short integers, stored in2 bytes, cover a smaller range of numbers (forexample, -32,768 through 32,767) than do longintegers (for example, -2,147,483,648 through2,147,483,647), which are stored in 4 bytes.

Also called integral number. See also floating-point notation

byte

n. Short for binary term. A unit of data, todayalmost always consisting of 8 bits. A byte canrepresent a single character, such as a letter, adigit, or a punctuation mark. Because a byterepresents only a small amount of information,amounts of computer memory and storage areusually given in kilobytes (1,024 bytes),



range from 0 to 127. Most PC-based systemsuse an 8-bit extended ASCII code, with an extra128 characters used to represent special

symbols, foreign-language characters, andgraphic symbols. See also ASCII, character,EBCDIC, extended ASCII, standard ASCII.

extended ASCII

n. Any set of characters assigned to ASCII

values between decimal 128 and 255(hexadecimal 80 through FF). The specificcharacters assigned to the extended ASCIIcodes vary between computers and betweenprograms, fonts, or graphics characters.Extended ASCII adds capability by allowing for

128 additional characters, such as accentedletters, graphics characters, and specialsymbols. See also ASCII.

C++





object-oriented programmingn. A programming paradigm in which a programis viewed as a collection of discrete objects thatare self-contained collections of data structuresand routines that interact with other objects.

Acronym: OOP. See also C++, object (definition

2), Objective-C.


n. A programming paradigm in which a programis viewed as a collection of discrete objects thatare self-contained collections of data structures

and routines that interact with other objects. Acronym: OOP. See also C++, object (definition2), Objective-C.

object

n. 1. Short for object code (machine-readable

code). 2. In object-oriented programming, avariable comprising both routines and data thatis treated as a discrete entity. See also abstractdata type, module (definition 1), object-orientedprogramming. 3. In graphics, a distinct entity.




modulen. 1. In programming, a collection of routinesand data structures that performs a particulartask or implements a particular abstract datatype. Modules usually consist of two parts: aninterface, which lists the constants, data types,

variables, and routines that can be accessed byother modules or routines, and animplementation, which is private (accessible onlyto the module) and which contains the sourcecode that actually implements the routines inthe module. See also abstract data type,

information hiding, Modula-2, modularprogramming. 2. In hardware, a self-containedcomponent that can provide a complete functionto a system and can be interchanged with othermodules that provide similar functions. See alsomemory card, SIMM.

abstract data type




performed with it. An abstract data type is moregeneralized than a data type constrained by theproperties of the objects it contains-for example,

the data type "pet" is more generalized than thedata types "pet dog," "pet bird," and "pet fish."The standard example used in illustrating anabstract data type is the stack", a small portionof memory used to store information, generallyon a temporary basis. As an abstract data type,

the stack is simply a structure onto which valuescan be pushed (added) and from which they canbe popped (removed). The type of value, suchas integer, is irrelevant to the definition.

The way in which the program performsoperations on abstract data types is

encapsulated, or hidden, from the rest of theprogram. Encapsulation enables theprogrammer to change the definition of the datatype or its operations without introducing errorsto the existing code that uses the abstract datatype. Abstract data types represent an

intermediate step between traditionalprogramming and object-oriented programming.See also data type, object-orientedprogramming.



data type

n. In programming, a definition of a set of data

that specifies the possible range of values of theset, the operations that can be performed onthe values, and the way in which the values arestored in memory. Defining the data type allowsa computer to manipulate the dataappropriately. Data types are most oftensupported in high-level languages and ofteninclude types such as real, integer, floatingpoint, character, Boolean, and pointer. How alanguage handles data typing is one of its majorcharacteristics. See also cast, constant,enumerated data type, strong typing, typechecking, user-defined data type, variable, weak

typing.

toolbox

n. A set of predefined (and usually precompiled)routines a programmer can use in writing aprogram for a particular machine, environment,

or application. Also called toolkit. See also library (definition 1).

Toolbox



n. A set of routines stored mostly in the read-only memory of a Macintosh that providesapplication programmers with the tools needed

to support the graphical interface characteristicof the computer. Also called User InterfaceToolbox.

disk drive

n. An electromechanical device that reads fromand writes to disks. The main components of adisk drive include a spindle on which the disk ismounted, a drive motor that spins the disk whenthe drive is in operation, one or more read/writeheads, a second motor that positions the

read/write head(s) over the disk, and controllercircuitry that synchronizes read/write activitiesand transfers information to and from thecomputer. Two types of disk drives are incommon use: floppy disk drives and hard disk drives. Floppy disk drives are designed to accept

removable disks in either 5.25-inch or 3.5-inchformat; hard disk drives are faster, high-capacitystorage units that are completely enclosed in aprotective case.



paradigm

n. An archetypal example or pattern that

provides a model for a process or systemarchitecture

n. 1. The physical construction or design of acomputer system and its components. See alsocache, CISC, closed architecture, network

architecture, open architecture, pipelining, RISC.2. The data-handling capacity of amicroprocessor. 3. The design of applicationsoftware incorporating protocols and the meansfor expansion and interfacing with otherprograms.

cache

\kash\ n. A special memory subsystem in whichfrequently used data values are duplicated forquick access. A memory cache stores thecontents of frequently accessed RAM locationsand the addresses where these data items are

stored. When the processor references anaddress in memory, the cache checks to seewhether it holds that address. If it does hold theaddress, the data is returned to the processor; if



it does not, a regular memory access occurs. A cache is useful when RAM accesses are slowcompared with the microprocessor speed,

because cache memory is always faster thanmain RAM memory. See also disk cache, waitstate.

disk

n. 1. A round, flat piece of flexible plastic coated

with a magnetic material that can be electricallyinfluenced to hold information recorded in digital(binary) form and encased in a protective plastic

jacket to protect them from damage andcontamination. Also called floppy, floppy disk,microfloppy disk. Compare compact disc, disc. 2.

See hard drive compact disc

n. 1. An optical storage medium for digital data,usually audio. A compact disc is a nonmagnetic,polished metal disc with a protective plasticcoating that can hold up to 74 minutes of high-fidelity recorded sound. The disk is read by anoptical scanning mechanism that uses a high-intensity light source, such as a laser, andmirrors. Also called optical disc. 2. A technology



Electrical Industries Association, thisRecommended Standard (RS) defines thespecific lines and signal characteristics used by

serial communications controllers to standardizethe transmission of serial data between devices.The letter C denotes that the current version of the standard is the third in a series. See alsoCTS, DSR , DTR , RTS, RXD, TXD.


n. Processing that involves the more or lesscontinuous participation of the user. Such acommand/response mode is characteristic of microcomputers. Compare batch processing (definition 2).

interactive program


handshake



multitude of standards affecting differentaspects of communication, such as file transfer(for example, XMODEM and ZMODEM),

handshaking (for example, XON/XOFF), andnetwork transmissions (for example, CSMA/CD).See also ISO/OSI model, SNA .

TCP/IP

n. Acronym for Transmission Control

Protocol/Internet Protocol. A protocol suite (orset of protocols) developed by the Departmentof Defense for communications overinterconnected, sometimes dissimilar, networks.It is built into the UNIX system and has becomethe de facto standard for data transmission over

networks, including the Internet1jan2006

spam1

n. An unsolicited e-mail message sent to manyrecipients at one time, or a news article posted

simultaneously to many newsgroups. Spam isthe electronic equivalent of junk mail. In mostcases, the content of a spam message or articleis not relevant to the topic of the newsgroup or



the interests of the recipient; spam is an abuseof the Internet in order to distribute a message(usually commercial or religious) to a huge

number of people at minimal cost.

spam2

vb. To distribute unwanted, unrequested mailwidely on the Internet by posting a message totoo many recipients or too many newsgroups.

The act of distributing such mail, known asspamming, angers most Internet users and hasbeen known to invite retaliation, often in theform of return spamming that can flood andpossibly disable the electronic mailbox of theoriginal spammer

6jan06

ADSL

n. Acronym for asymmetric digital subscriberline. Technology and equipment allowing high-speed digital communication, including video

signals, across an ordinary twisted-pair copperphone line, with speeds up to 8 Mbps (megabitsper second) downstream (to the customer) andup to 640 Kbps (kilobits per second) upstream.



telephone-based communications. For the sakeof compatibility and interoperability, a groupcalled the VoIP Forum promotes product

development based on the ITU-T H.323standard for transmission of multimedia over theInternet. Also called Internet telephony. Seealso H.323.

volatile memory

n. 1. Memory, such as RAM, that loses its datawhen the power is shut off. Compare nonvolatilememory. 2. Memory used by a program that canchange independently of the program, such asmemory shared by another program or by aninterrupt service routine.

nonvolatile memory

n. A storage system that does not lose datawhen power is removed from it. Intended torefer to core memory, ROM, EPROM, flashmemory, bubble memory, or battery-backedCMOS RAM, the term is occasionally used inreference to disk subsystems as well. See alsobubble memory, CMOS RAM, core, EPROM, flashmemory, ROM.



flash memory

n. A type of nonvolatile memory. Flash memory

is similar to EEPROM memory in function but itmust be erased in blocks, whereas EEPROM canbe erased one byte at a time. Because of itsblock-oriented nature, flash memory iscommonly used as a supplement to orreplacement for hard disks in portablecomputers. In this context, flash memory eitheris built into the unit or, more commonly, isavailable as a PC Card that can be plugged intoa PCMCIA slot. A disadvantage of the block-oriented nature of flash memory is that it cannotbe practically used as main memory (RAM)because a computer needs to be able to write to

memory in single-byte increments. See alsoEEPROM, nonvolatile memory, PC Card, PCMCIA slot

IP

n. Acronym for Internet Protocol. The protocol

within TCP/IP that governs the breakup of datamessages into packets, the routing of thepackets from sender to destination network andstation, and the reassembly of the packets intothe original data messages at the destination. IP



runs at the internetwork layer in the TCP/IPmodel-equivalent to the network layer in theISO/OSI reference model. See also ISO/OSI

reference model, TCP/IP. Compare TCP.

TCP

n. Acronym for Transmission Control Protocol.The protocol within TCP/IP that governs thebreakup of data messages into packets to be

sent via IP (Internet Protocol), and thereassembly and verification of the completemessages from packets received by IP. A connection-oriented, reliable protocol (reliable inthe sense of ensuring error-free delivery), TCPcorresponds to the transport layer in the

ISO/OSI reference model. See also ISO/OSIreference model, packet, TCP/IP. Compare UDP.

packet

n. 1. A unit of information transmitted as awhole from one device to another on a network.2. In packet-switching networks, a transmissionunit of fixed maximum size that consists of binary digits representing both data and aheader containing an identification number,source and destination addresses, and



is electrically and physically incompatible withthe IBM PC/AT bus. Unlike the PC/AT bus, theMicro Channel functions as either a 16-bit or a

32-bit bus. The Micro Channel also can bedriven independently by multiple bus masterprocessors.

PS/2 bus


bus

n. A set of hardware lines (conductors) used fordata transfer among the components of acomputer system. A bus is essentially a sharedhighway that connects different parts of the

system-including the processor, disk-drivecontroller, memory, and input/output ports-andenables them to transfer information. The busconsists of specialized groups of lines that carrydifferent types of information. One group of lines carries data; another carries memoryaddresses (locations) where data items are to befound; yet another carries control signals. Busesare characterized by the number of bits they cantransfer at a single time, equivalent to thenumber of wires within the bus. A computer



with a 32-bit address bus and a 16-bit data bus,for example, can transfer 16 bits of data at atime from any of 232 memory locations. Most

PCs contain one or more expansion slots intowhich additional boards can be plugged toconnect them to the bus.

hard disk

n. A device containing one or more inflexible

platters coated with material in which data canbe recorded magnetically, together with theirread/write heads, the head-positioningmechanism, and the spindle motor in a sealedcase that protects against outside contaminants.The protected environment allows the head to

fly 10 to 25 millionths of an inch above thesurface of a platter rotating typically at 3,600 to7,200 rpm; therefore, much more data can bestored and accessed much more quickly than ona floppy disk. Most hard disks contain from twoto eight platters. Also called hard disk drive.Compare floppy disk .

soft copy




hard copy

n. Printed output on paper, film, or other

permanent medium. Compare soft copy.URL

n. Acronym for Uniform Resource Locator. Anaddress for a resource on the Internet. URLs areused by Web browsers to locate Internet

resources. A URL specifies the protocol to beused in accessing the resource (such as http: fora World Wide Web page or ftp: for an FTP site),the name of the server on which the resourceresides (such as //www.whitehouse.gov), and,optionally, the path to a resource (such as anHTML document or a file on that server). See


HDSL

n. Acronym for High-bit-rate Digital Subscriber

Line. A form of DSL, HDSL is a protocol fordigital transmission of data over standardcopper telecommunications lines (as opposed tofiber-optic lines) at rates of 1.544 Mbps in both



directions. Also called High-data-rate DigitalSubscriber Line. See also DSL.

broadbandadj. Of or relating to communications systems inwhich the medium of transmission (such as awire or fiber-optic cable) carries multiplemessages at a time, each message modulatedon its own carrier frequency by means of

modems. Broadband communication is found inwide area networks. Compare baseband.

8JAN06

optical communications

n. The use of light and of light-transmittingtechnology, such as optical fibers and lasers, insending and receiving data, images, or sound.

n. A disk drive that reads and often can writedata on optical (compact) discs. Examples of optical drives include CD-ROM drives and WORM

disk drives. See also CD-ROM drive, compactdisc, WORM.

optical fiber



n. A thin strand of transparent material used tocarry optical signals. Optical fibers areconstructed from special kinds of glass and

plastic, and they are designed so that a beam of light introduced at one end will remain withinthe fiber, reflecting off the inner surfaces as ittravels down the length of the fiber. Opticalfibers are inexpensive, compact, and lightweightand are often packaged many hundred to a

single cable. See also fiber optics.

optical mouse

n. A type of mouse that uses a pair of light-emitting diodes (LEDs) and a special reflectivegrid pad to detect motion. The two lights are of

different colors, and the special mouse pad hasa grid of lines in the same colors, one color forvertical lines and another for horizontal lines.Light detectors paired with the LEDs sense whena colored light passes over a line of the samecolor, indicating the direction of movement. Seealso mouse. Compare mechanical mouse,optomechanical mouse.

fiber optics





strands of glass or other transparent material,with dozens or hundreds of strands housed in asingle cable. Optical fibers are essentiallyimmune to electromagnetic interference. Seealso optical fiber.

mechanical mouse






voice recognition



request or a statement can be made, is moredifficult, although advances are being made inthis area. Also called speech recognition. Seealso artificial intelligence, dictation software,neural network .

neural network







pattern recognition



thumbnail




thumbnails of images (which can be loadedmuch more quickly by the Web browser than thefull-size image). Many of these thumbnails can

be clicked on to load the complete version of theimage

25jan06wednes

ADSL

n. Acronym for asymmetric digital subscriberline. Technology and equipment allowing high-speed digital communication, including videosignals, across an ordinary twisted-pair copperphone line, with speeds up to 8 Mbps (megabitsper second) downstream (to the customer) andup to 640 Kbps (kilobits per second) upstream.

ADSL access to the Internet is offered by someregional telephone companies, offering usersfaster connection times than those availablethrough connections made over standard phonelines. Also called asymmetric digital subscriberloop. Compare SDSL.


n. A protocol for servers on the Internet thatreceive, store, and transmit e-mail and for



clients on computers that connect to the serversto download and upload e-mail. Acronym: POP.

25jan06digital signal processor

n. An integrated circuit designed for high-speeddata manipulation and used in audio,communications, image manipulation, and other

data acquisition and data control applications. Acronym: DSP

hardware

n. The physical components of a computersystem, including any peripheral equipment suchas printers, modems, and mouse devices.Compare firmware, software

26jan06

cookie

n. 1. A block of data that a server returns to aclient in response to a request from the client. 2.On the World Wide Web, a block of data that aWeb server stores on a client system. When a






cache






benchmark 1




benchmark 2





2feb06

thumbnail


Java

n. An object-oriented programming languagedeveloped by Sun Microsystems. Similar to C++,Java is smaller, more portable, and easier to usethan C++ because it is more robust and it



manages memory on its own. Java was alsodesigned to be secure and platform-neutral(meaning that it can be run on any platform)

through the fact that Java programs arecompiled into bytecode, which is not refined tothe point of relying on platform-specificinstructions and runs on a computer in a specialsoftware environment known as a virtualmachine. This characteristic of Java makes it a

useful language for programming Webapplications, since users access the Web frommany types of computers. Java is used inprogramming small applications, or applets, forthe World Wide Web, as well as in creatingdistributed network applications. See also bytecode, Java applet, Jini, object-orientedprogramming.

platform

n. 1. The foundation technology of a computersystem. Because computers are layered devicescomposed of a chip-level hardware layer, afirmware and operating-system layer, and anapplications program layer, the bottommostlayer of a machine is often called a platform. 2.



multiplexer

n. A device for funneling several different

streams of data over a common communicationsline. Multiplexers are used either to attach manycommunications lines to a smaller number of communications ports or to attach a largenumber of communications ports to a smallernumber of communications lines. Acronym: MUX.

multiplexer channel

decoder

n. 1. A device or program routine that convertscoded data back to its original form. This can

mean changing unreadable or encrypted codesinto readable text or changing one code toanother, although the latter type of decoding isusually referred to as conversion. Compare conversion. 2. In electronics and hardware, atype of circuit that produces one or moreselected output signals based on thecombination of input signals it receives.

Wednesday, March 28, 2007

|



NotesMemory

flash memoryn. A type of nonvolatile memory. Flash memoryis similar to EEPROM memory in function but itmust be erased in blocks, whereas EEPROM canbe erased one byte at a time. Because of itsblock-oriented nature, flash memory is

commonly used as a supplement to orreplacement for hard disks in portablecomputers. In this context, flash memory eitheris built into the unit or, more commonly, isavailable as a PC Card that can be plugged intoa PCMCIA slot. A disadvantage of the block-oriented nature of flash memory is that it cannotbe practically used as main memory (RAM)because a computer needs to be able to write tomemory in single-byte increments. See alsoEEPROM, nonvolatile memory

nonvolatile memory

n. A storage system that does not lose datawhen power is removed from it. Intended torefer to core memory, ROM, EPROM, flashmemory, bubble memory, or battery-backed



CMOS RAM, the term is occasionally used inreference to disk subsystems as well. See alsobubble memory, CMOS RAM, core, EPROM, flash

memory 19Octo04

contiguous data structure/10nov04n. A data structure, such as an array, that isstored in a consecutive set of memory locations.See also data structure. Compare noncontiguous

data structure.noncontiguous data structure/10nov04n. In programming, a data structure whoseelements are not stored contiguously inmemory. Data structures such as graphs andtrees, whose elements are connected bypointers, are noncontiguous data structures.Compare contiguous data structure.Bit/10nov04n. Short for binary digit. The smallest unit of information handled by a computer. One bitexpresses a 1 or a 0 in a binary numeral, or atrue or false logical condition, and is represented

physically by an element such as a high or lowvoltage at one point in a circuit or a small spoton a disk magnetized one way or the other. A single bit conveys little information a human



would consider meaningful. A group of 8 bits,however, makes up a byte, which can be usedto represent many types of information, such as

a letter of the alphabet, a decimal digit, or othercharacter. See also ASCII, binary1, bytebyte/10nov04n. Short for binary term. A unit of data, todayalmost always consisting of 8 bits. A byte canrepresent a single character, such as a letter, a

digit, or a punctuation mark. Because a byterepresents only a small amount of information,amounts of computer memory and storage areusually given in kilobytes (1,024 bytes),megabytes (1,048,576 bytes), or gigabytes(1,073,741,824 bytes). Abbreviation: B. See alsobit, gigabyte, kilobyte, megabyte. Compareoctet, word.

flash memoryn. A type of nonvolatile memory. Flash memoryis similar to EEPROM memory in function but itmust be erased in blocks, whereas EEPROM can

be erased one byte at a time. Because of itsblock-oriented nature, flash memory iscommonly used as a supplement to orreplacement for hard disks in portable



computers. In this context, flash memory eitheris built into the unit or, more commonly,

is available as a PC Card that can be pluggedinto a PCMCIA slot. A disadvantage of the block-oriented nature of flash memory is that it cannotbe practically used as main memory (RAM)because a computer needs to be able to write tomemory in single-byte increments. See also

EEPROM, nonvolatile memory, PC Card, PCMCIA slot.

kernel

n. The core of an operating system-the portion

of the system that manages memory, files, andperipheral devices; maintains the time and date;launches applications; and allocates systemresources.

Wednesday, May 02, 2007

Linux

n. A version of the UNIX System V Release 3.0kernel developed for PCs with 80386 and higher-level microprocessors. Developed by Linus



Torvalds (for whom it is named) along withnumerous collaborators worldwide, Linux isdistributed free, and its source code is open to

modification by anyone who chooses to work onit, although some companies distribute it as partof a commercial package with Linux-compatibleutilities. The Linux kernel works with the GNUutilities developed by the Free SoftwareFoundation, which did not produce a kernel. It is

used by some as an operating system fornetwork servers and in the 1998/1999timeframe began to gain increased visibilitythrough support from vendors such as IBM andCompaq. See also free software, GNU, kernel,UNIX.

UNIX

n. A multiuser, multitasking operating system.Originally developed by Ken Thompson andDennis Ritchie at AT&T Bell Laboratories from1969 through 1973 for use on minicomputers,UNIX has evolved into a complex, powerfuloperating system that, because it is written inthe C language, is more portable-that is, lessmachine-specific-than many other operatingsystems. UNIX has been released in a wide



variety of versions, or flavors, including System V (developed by AT&T for commercial release;many current flavors on based on it), BSD UNIX

(freeware developed at the University of California Berkeley, which has spun off manyrelated flavors) AIX (a version of System Vadapted by IBM to run on RISC-basedworkstations), A/UX (a graphical version for theMacintosh), Linux (a newer version that runs on

the Intel chip), and SunOS (based on BSD UNIXand available on Sun workstations). Manyflavors of UNIX are available free. With someflavors, the source code is also free, making itan instrumental part of the Open Sourcemovement. UNIX is a widely used as a network operating system, especially in conjunction withthe Internet. See also BSD UNIX, Linux, opensource, System V.

open source

n. The practice of making the source code(program instructions) for a software productfreely available, at no cost, to interested usersand developers, even though they were notinvolved in creating the original product. Thedistributors of open source software expect and



encourage users and outside programmers toexamine the code in order to identify problems,and to modify the code with suggested

improvements and enhancements. Widely usedopen-source products include the Linuxoperating system and the Apache web server.

open system

n. 1. In communications, a computer network

designed to incorporate all devices-regardless of the manufacturer or model-that can use thesame communications facilities and protocols. 2.In reference to computer hardware or software,a system that can accept add-ons produced bythird-party suppliers. See also open architecture

(definition 1).open architecture

n. 1. Any computer or peripheral design that haspublished specifications. A publishedspecification lets third parties develop add-onhardware for a computer or device. Compare closed architecture (definition 1). 2. A designthat provides for expansion slots on themotherboard, thereby allowing the addition of



boards to enhance or customize a system.Compare closed architecture (definition 2).

closed architecturen. 1. Any computer design whose specificationsare not freely available. Such proprietaryspecifications make it difficult or impossible forthird-party vendors to create ancillary devicesthat work correctly with a closed-architecture

machine; usually only its original maker canbuild peripherals and add-ons for such amachine. Compare open architecture (definition1). 2. A computer system that provides noexpansion slots for adding new types of circuitboards within the system unit. The original

Apple Macintosh was an example of a closedarchitecture. Compare open architecture (definition 2).

operating system

n. The software that controls the allocation andusage of hardware resources such as memory,central processing unit (CPU) time, disk space,and peripheral devices. The operating system isthe foundation software on which applicationsdepend. Popular operating systems include



Windows 98, Windows NT, Mac OS, and UNIX. Acronym: OS. Also called executive.

RAMn. Acronym for random access memory.Semiconductor-based memory that can be readand written by the central processing unit (CPU)or other hardware devices. The storagelocations can be accessed in any order. Note

that the various types of ROM memory arecapable of random access but cannot be writtento. The term RAM, however, is generallyunderstood to refer to volatile memory that canbe written to as well as read. Compare core,EPROM, flash memory, PROM, ROM (definition

2).ROM

n. 1. Acronym for read-only memory. A semiconductor circuit into which code or data ispermanently installed by the manufacturingprocess. The use of this technology iseconomically viable only if the chips areproduced in large quantities; experimentaldesigns or small volumes are best handled usingPROM or EPROM. 2. Acronym for read-only



memory. Any semiconductor circuit serving as amemory that contains instructions or data thatcan be read but not modified (whether placed

there by manufacturing or by a programmingprocess, as in PROM and EPROM). See also EEPROM, EPROM, PROM

volati le memory

n. 1. Memory, such as RAM, that loses its data

when the power is shut off. Compare nonvolatilememory. 2. Memory used by a program that canchange independently of the program, such asmemory shared by another program or by aninterrupt service routine.

nonvolatile memory

n. A storage system that does not lose datawhen power is removed from it. Intended torefer to core memory, ROM, EPROM, flashmemory, bubble memory, or battery-backedCMOS RAM, the term is occasionally used inreference to disk subsystems as well. See also bubble memory, CMOS RAM, core, EPROM, flashmemory, ROM.

flash memory



n. A type of nonvolatile memory. Flash memoryis similar to EEPROM memory in function but itmust be erased in blocks, whereas EEPROM can

be erased one byte at a time. Because of itsblock-oriented nature, flash memory iscommonly used as a supplement to orreplacement for hard disks in portablecomputers. In this context, flash memory eitheris built into the unit or, more commonly, is

available as a PC Card that can be plugged intoa PCMCIA slot. A disadvantage of the block-oriented nature of flash memory is that it cannotbe practically used as main memory (RAM)because a computer needs to be able to write tomemory in single-byte increments. See also EEPROM, nonvolatile memory, PC Card, PCMCIA slot.

hacker

n. 1. A computerphile; a person who is totallyengrossed in computer technology andcomputer programming or who likes to examinethe code of operating systems and otherprograms to see how they work. 2. A person,more commonly considered a cracker, who usescomputer expertise for illicit ends, such as by



gaining access to computer systems withoutpermission and tampering with programs anddata. Also called cracker.


n. Memory access that does not involve themicroprocessor and is frequently used for datatransfer directly between memory and anintelligent peripheral device, such as a disk

drive. Acronym: DMA.





n. In programming, a data set defined by theprogrammer in terms of the information it cancontain and the operations that can beperformed with it. An abstract data type is moregeneralized than a data type constrained by the



properties of the objects it contains-for example,the data type "pet" is more generalized than thedata types "pet dog," "pet bird," and "pet fish."

The standard example used in illustrating anabstract data type is the stack", a small portionof memory used to store information, generallyon a temporary basis. As an abstract data type,the stack is simply a structure onto which valuescan be pushed (added) and from which they can

be popped (removed). The type of value, suchas integer, is irrelevant to the definition.

The way in which the program performsoperations on abstract data types isencapsulated, or hidden, from the rest of theprogram. Encapsulation enables the

programmer to change the definition of the datatype or its operations without introducing errorsto the existing code that uses the abstract datatype. Abstract data types represent anintermediate step between traditionalprogramming and object-oriented programming.


encapsulation



n. In object-oriented programming, thepackaging of attributes (properties) andfunctionality (methods or behaviors) to create

an object that is essentially a black box —onewhose internal structure remains private andwhose services can be accessed by other objectsonly through messages passed via a clearlydefined interface (the programming equivalentof a mailbox or telephone line). Encapsulation


fuzzy logic

n. A form of logic used in some expert systemsand other artificial-intelligence applications inwhich variables can have degrees of truthfulnessor falsehood represented by a range of valuesbetween 1 (true) and 0 (false). With fuzzy logic,the outcome of an operation can be expressedas a probability rather than as a certainty. Forexample, an outcome might be probably true,



possibly true, possibly false, or probably false.See also expert system.

expert system/ 2dec04n. An application program that makesdecisions or solves problems in aparticular field, such as finance ormedicine, by using know ledge andanalytical rules defined by experts in the

field. It uses two components, aknow ledge base and an inference engine,to form conclusions. Additional toolsinclude user interfaces and explanationfacilities, which enable the system to justify or explain its conclusions as well as

allow ing developers to run checks on theoperating system. See also artificialintelligence, inference engine, intelligentdatabase, encapsulation

n. In object-oriented programming, thepackaging of attributes (properties) and

functionality (methods or behaviors) to createan object that is essentially a black box —onewhose internal structure remains private andwhose services can be accessed by other objectsonly through messages passed via a clearly



defined interface (the programming equivalentof a mailbox or telephone line). Encapsulationensures that the object providing service can

prevent other objects from manipulating its dataor procedures directly, and it enables the objectrequesting service to ignore the details of howthat service is provided. See also informationhiding.

black box

n. A unit of hardware or software whose internalstructure is unknown but whose function isdocumented. The internal mechanics of thefunction do not matter to a designer who uses ablack box to obtain that function. For example, a

memory chip can be viewed as a black box.Many people use memory chips and designthem into computers, but generally onlymemory chip designers need to understand theirinternal operation.

encapsulate

vb. 1. To treat a collection of structuredinformation as a whole without affecting ortaking notice of its internal structure. Incommunications, a message or packet



constructed according to one protocol, such as aTCP/IP packet, may be taken with its formattingdata as an undifferentiated stream of bits that is

then broken up and packaged according to alower-level protocol (for example, as ATMpackets) to be sent over a particular network; atthe destination, the lower-level packets areassembled, re-creating the message asformatted for the encapsulated protocol. See

also ATM (definition 1). 2. In object-orientedprogramming, to keep the implementationdetails of a class a separate file whose contentsdo not need to be known by a programmerusing that class. See also object-orientedprogramming, TCP/IP.







n. A set of routines used by an applicationprogram to direct the performance of procedures by the computer's operating system. Acronym: API. Also called application programinterface.







operating system

n. The software that controls the allocation andusage of hardware resources such as memory,central processing unit (CPU) time, disk space,and peripheral devices. The operating system isthe foundation software on which applicationsdepend. Popular operating systems includeWindows 98, Windows NT, Mac OS, and UNIX. Acronym: OS. Also called executive.





AT, IRQ

spam 1




spam 2





31dec05

filter










e-mail fi lter










pixel map



31dec05

BIOS





turned on. Although critical to performance, theBIOS is usually invisible to computer users. See also AMI BIOS, CMOS setup, Phoenix BIOS,ROM BIOS. Compare Toolbox.

flip-flop


multivibratorfloat








n. An arithmetic operation performed ondata stored in floating-point notation.Floating-point operations are usedwherever numbers may have either

fractional or irrational parts, as inspreadsheets and computer-aided design(CAD). Therefore, one measure of acomputer's power is how many m ill ions of floating-point operations per second(MFLOPS or megaflops) it can perform. Acronym: FLOP. Also called floating-pointoperation. See also floating-pointnotation, MFLOfloating-point notation

n. A numeric format that can be used torepresent very large real numbers and very



take less time than floating-point operations.See also floating-point notation, integer.

integern. 1. A positive or negative "whole" number,such as 37, -50, or 764. 2. A data typerepresenting whole numbers. Calculationsinvolving only integers are much faster thancalculations involving floating-point numbers, so

integers are widely used in programming forcounting and numbering purposes. Integers canbe signed (positive or negative) or unsigned(positive). They can also be described as long orshort, depending on the number of bytesneeded to store them. Short integers, stored in

2 bytes, cover a smaller range of numbers (forexample, -32,768 through 32,767) than do longintegers (for example, -2,147,483,648 through2,147,483,647), which are stored in 4 bytes. Also called integral number. See also floating-point notation

byte

n. Short for b inary term. A unit of data, todayalmost always consisting of 8 bits. A byte canrepresent a single character, such as a letter, a



digit, or a punctuation mark. Because a byterepresents only a small amount of information,amounts of computer memory and storage are

usually given in kilobytes (1,024 bytes),megabytes (1,048,576 bytes), or gigabytes(1,073,741,824 bytes). Abbreviation: B. See also bit, gigabyte, kilobyte, megabyte. Compare octet, word.

character

n. A letter, number, punctuation mark, or othersymbol or control code that is represented to acomputer by one unit-1 byte-of information. A character is not necessarily visible, either on thescreen or on paper; a space, for example, is as

much a character as is the letter a or any of thedigits 0 through 9. Because computers mustmanage not only so-called printable charactersbut also the look (formatting) and transfer of electronically stored information, a character canadditionally indicate a carriage return or aparagraph mark in a word-processed document.It can be a signal to sound a beep, begin a newpage, or mark the end of a file. See also ASCII,control character, EBCDIC.

nibble or nybble




ascii

n. In an FTP client program, the command thatinstructs the FTP server to send or receive filesas ASCII text. See also ASCII, FTP client Compare binary2

ASCII

n. Acronym for A merican Standard Code forInformation Interchange. A coding schemeusing 7 or 8 bits that assigns numeric values toup to 256 characters, including letters,numerals, punctuation marks, controlcharacters, and other symbols. ASCII was

developed in 1968 to standardize datatransmission among disparate hardware andsoftware systems and is built into mostminicomputers and all PCs. ASCII is divided intotwo sets: 128 characters (standard ASCII) andan additional 128 (extended ASCII). See also

ASCII file, character, character code, controlcharacter, extended ASCII, standard ASCII.Compare EBCDIC.

EBCDIC.



ASCII character set

n. A standard 7-bit code for representing ASCII

characters using binary values; code valuesrange from 0 to 127. Most PC-based systemsuse an 8-bit extended ASCII code, with an extra128 characters used to represent specialsymbols, foreign-language characters, andgraphic symbols. See also ASCII, character,EBCDIC, extended ASCII, standard ASCII.

extended ASCII

n. Any set of characters assigned to ASCIIvalues between decimal 128 and 255(hexadecimal 80 through FF). The specificcharacters assigned to the extended ASCII

codes vary between computers and betweenprograms, fonts, or graphics characters.Extended ASCII adds capability by allowing for128 additional characters, such as accentedletters, graphics characters, and specialsymbols. See also ASCII.

C++

n. An object-oriented version of the Cprogramming language, developed by Bjarne



Stroustrup in the early 1980s at BellLaboratories and adopted by a number of vendors, including Apple Computer and Sun



n. A programming paradigm in which a programis viewed as a collection of discrete objects that

are self-contained collections of data structuresand routines that interact with other objects. Acronym: OOP. See also C++, object (definition2), Objective-C.


n. A programming paradigm in which a programis viewed as a collection of discrete objects thatare self-contained collections of data structuresand routines that interact with other objects. Acronym: OOP. See also C++, object (definition2), Objective-C.

object

n. 1. Short for object code (machine-readablecode). 2. In object-oriented programming, avariable comprising both routines and data that



is treated as a discrete entity. See also abstractdata type, module (definition 1), object-orientedprogramming. 3. In graphics, a distinct entity.


module

n. 1. In programming, a collection of routinesand data structures that performs a particular

task or implements a particular abstract datatype. Modules usually consist of two parts: aninterface, which lists the constants, data types,variables, and routines that can be accessed byother modules or routines, and animplementation, which is private (accessible only

to the module) and which contains the sourcecode that actually implements the routines inthe module. See also abstract data type,information hiding, Modula-2, modularprogramming. 2. In hardware, a self-containedcomponent that can provide a complete functionto a system and can be interchanged with othermodules that provide similar functions. See also memory card, SIMM.

abstract data type




performed with it. An abstract data type is moregeneralized than a data type constrained by theproperties of the objects it contains-for example,the data type "pet" is more generalized than thedata types "pet dog," "pet bird," and "pet fish."The standard example used in illustrating an

abstract data type is the stack", a small portionof memory used to store information, generallyon a temporary basis. As an abstract data type,the stack is simply a structure onto which valuescan be pushed (added) and from which they canbe popped (removed). The type of value, suchas integer, is irrelevant to the definition.

The way in which the program performsoperations on abstract data types isencapsulated, or hidden, from the rest of theprogram. Encapsulation enables theprogrammer to change the definition of the data

type or its operations without introducing errorsto the existing code that uses the abstract datatype. Abstract data types represent anintermediate step between traditionalprogramming and object-oriented programming.




data typen. In programming, a definition of a set of datathat specifies the possible range of values of theset, the operations that can be performed onthe values, and the way in which the values arestored in memory. Defining the data type allows

a computer to manipulate the dataappropriately. Data types are most oftensupported in high-level languages and ofteninclude types such as real, integer, floatingpoint, character, Boolean, and pointer. How alanguage handles data typing is one of its major

characteristics. See also cast, constant,enumerated data type, strong typing, typechecking, user-defined data type, variable, weak typing.

toolbox

n. A set of predefined (and usually precompiled)routines a programmer can use in writing aprogram for a particular machine, environment,or application. Also called toolkit. See also library (definition 1).



Toolbox

n. A set of routines stored mostly in the read-

only memory of a Macintosh that providesapplication programmers with the tools neededto support the graphical interface characteristicof the computer. Also called User InterfaceToolbox.

disk drive

n. An electromechanical device that reads fromand writes to disks. The main components of adisk drive include a spindle on which the disk ismounted, a drive motor that spins the disk when

the drive is in operation, one or more read/writeheads, a second motor that positions theread/write head(s) over the disk, and controllercircuitry that synchronizes read/write activitiesand transfers information to and from thecomputer. Two types of disk drives are incommon use: floppy disk drives and hard disk drives. Floppy disk drives are designed to acceptremovable disks in either 5.25-inch or 3.5-inchformat; hard disk drives are faster, high-capacity



storage units that are completely enclosed in aprotective case.

paradigmn. An archetypal example or pattern thatprovides a model for a process or system

architecture

n. 1. The physical construction or design of a

computer system and its components. See also cache, CISC, closed architecture, network architecture, open architecture, pipelining, RISC.2. The data-handling capacity of amicroprocessor. 3. The design of applicationsoftware incorporating protocols and the means

for expansion and interfacing with otherprograms.

cache


quick access. A memory cache stores thecontents of frequently accessed RAM locationsand the addresses where these data items arestored. When the processor references anaddress in memory, the cache checks to see



whether it holds that address. If it does hold theaddress, the data is returned to the processor; if it does not, a regular memory access occurs. A

cache is useful when RAM accesses are slowcompared with the microprocessor speed,because cache memory is always faster thanmain RAM memory. See also disk cache, waitstate.

disk

n. 1. A round, flat piece of flexible plastic coatedwith a magnetic material that can be electricallyinfluenced to hold information recorded in digital(binary) form and encased in a protective plastic

jacket to protect them from damage and

contamination. Also called floppy, floppy disk,microfloppy disk. Compare compact disc, disc. 2.See hard drive

compact disc

n. 1. An optical storage medium for digital data,usually audio. A compact disc is a nonmagnetic,polished metal disc with a protective plasticcoating that can hold up to 74 minutes of high-fidelity recorded sound. The disk is read by anoptical scanning mechanism that uses a high-



intensity light source, such as a laser, andmirrors. Also called optical disc. 2. A technologythat forms the basis of media such as CD-ROM,

CD-ROM/XA, CD-I, CD-R, DVI, and PhotoCD.These media are all compact disc-based butstore various types of digital information andhave different read/write capabilities.Documentation for compact disc formats can befound in books designated by the color of their

covers. For example, documentation for audiocompact discs is found in the Red Book. See also CD-I, CD-R , CD-ROM, CD-ROM/XA , DVI,Green Book (definition 2), Orange Book (definition 2), PhotoCD, Red Book (definition 2).3. See CD.

disc


RS-232-C standard



n. An accepted industry standard for serialcommunications connections. Adopted by theElectrical Industries Association, this

Recommended Standard (RS) defines thespecific lines and signal characteristics used byserial communications controllers to standardizethe transmission of serial data between devices.The letter C denotes that the current version of the standard is the third in a series. See also

CTS, DSR , DTR , RTS, RXD, TXD.


n. Processing that involves the more or lesscontinuous participation of the user. Such acommand/response mode is characteristic of

microcomputers. Compare batch processing (definition 2).

interactive program




handshake

n. A series of signals acknowledging that

communication or the transfer of informationcan take place between computers or otherdevices. A hardware handshake is an exchangeof signals over specific wires (other than thedata wires), in which each device indicates itsreadiness to send or receive data. A softwarehandshake consists of signals transmitted overthe same wires used to transfer data, as inmodem-to-modem communications overtelephone lines.

31dec05


n. A set of rules or standards designed to enablecomputers to connect with one another and toexchange information with as little error aspossible. The protocol generally accepted forstandardizing overall computer communicationsis a seven-layer set of hardware and softwareguidelines known as the OSI (Open SystemsInterconnection) model. A somewhat differentstandard, widely used before the OSI model wasdeveloped, is IBM's SNA (Systems Network



Architecture). The word protocol is often used,sometimes confusingly, in reference to amultitude of standards affecting different

aspects of communication, such as file transfer(for example, XMODEM and ZMODEM),handshaking (for example, XON/XOFF), andnetwork transmissions (for example, CSMA/CD).See also ISO/OSI model, SNA .

TCP/IP

n. Acronym for Transmission ControlProtocol/Internet Protocol. A protocol suite (orset of protocols) developed by the Departmentof Defense for communications overinterconnected, sometimes dissimilar, networks.

It is built into the UNIX system and has becomethe de facto standard for data transmission overnetworks, including the Internet

1jan2006

spam 1




(megabits per second) downstream (tothe customer) and up to 640 Kbps (kilobitsper second) upstream. ADSL access to the

Internet is offered by some regional telephonecompanies, offering users faster connectiontimes than those available through connectionsmade over standard phone lines. Also called asymmetric digital subscriber loop. Compare SDSL.

SDSL

n. Acronym for symmetric (or s ingle-line) d igitalsubscriber l ine, a digital telecommunicationstechnology that is a variation of HDSL. SDSLuses one pair of copper wire rather than two

pairs of wires and transmits at 1.544 Mbps.Compare ADSL.

VoIP

n. Acronym for Voice over IP. The use of theInternet Protocol (IP) for transmitting voicecommunications. VoIP delivers digitized audio inpacket form and can be used for transmittingover intranets, extranets, and the Internet. It isessentially an inexpensive alternative totraditional telephone communication over the



circuit-switched Public Switched TelephoneNetwork (PSTN). VoIP covers computer-to-computer, computer-to-telephone, and

telephone-based communications. For the sakeof compatibility and interoperability, a groupcalled the VoIP Forum promotes productdevelopment based on the ITU-T H.323standard for transmission of multimedia over theInternet. Also called Internet telephony. See

also H.323.

volati le memory

n. 1. Memory, such as RAM, that loses its datawhen the power is shut off. Compare nonvolatilememory. 2. Memory used by a program that can

change independently of the program, such asmemory shared by another program or by aninterrupt service routine.

nonvolatile memory

n. A storage system that does not lose datawhen power is removed from it. Intended torefer to core memory, ROM, EPROM, flashmemory, bubble memory, or battery-backedCMOS RAM, the term is occasionally used inreference to disk subsystems as well. See also



bubble memory, CMOS RAM, core, EPROM, flashmemory, ROM.

flash memoryn. A type of nonvolatile memory. Flash memoryis similar to EEPROM memory in function but itmust be erased in blocks, whereas EEPROM canbe erased one byte at a time. Because of itsblock-oriented nature, flash memory is

commonly used as a supplement to orreplacement for hard disks in portablecomputers. In this context, flash memory eitheris built into the unit or, more commonly, isavailable as a PC Card that can be plugged intoa PCMCIA slot. A disadvantage of the block-

oriented nature of flash memory is that it cannotbe practically used as main memory (RAM)because a computer needs to be able to write tomemory in single-byte increments. See also EEPROM, nonvolatile memory, PC Card, PCMCIA slot

IP

n. Acronym for Internet Protocol. The protocolwithin TCP/IP that governs the breakup of datamessages into packets, the routing of the



packets from sender to destination network andstation, and the reassembly of the packets intothe original data messages at the destination. IP

runs at the internetwork layer in the TCP/IPmodel-equivalent to the network layer in theISO/OSI reference model. See also ISO/OSIreference model, TCP/IP. Compare TCP.

TCP

n. Acronym for Transmission Control Protocol.The protocol within TCP/IP that governs thebreakup of data messages into packets to besent via IP (Internet Protocol), and thereassembly and verification of the completemessages from packets received by IP. A

connection-oriented, reliable protocol (reliable inthe sense of ensuring error-free delivery), TCPcorresponds to the transport layer in theISO/OSI reference model. See also ISO/OSIreference model, packet, TCP/IP. Compare UDP.

packet

n. 1. A unit of information transmitted as awhole from one device to another on a network.2. In packet-switching networks, a transmissionunit of fixed maximum size that consists of



binary digits representing both data and aheader containing an identification number,source and destination addresses, and

sometimes error-control data. See also packetswitching.

USB

n. Acronym for universal serial bus. A serial buswith a data transfer rate of 12 megabits per

second (Mbps) for connecting peripherals to amicrocomputer. USB can connect up to 127peripherals, such as external CD-ROM drives,printers, modems, mice, and keyboards, to thesystem through a single, general-purpose port.This is accomplished by daisy chaining

peripherals together. USB is designed to supportthe ability to automatically add and configurenew devices and the ability to add such deviceswithout having to shut down and restart thesystem (hot plugging). USB was developed byIntel, Compaq, DEC, IBM, Microsoft, NEC, andNorthern Telecom. It competes with DEC's

ACCESS.bus for lower-speed applications. See also bus, daisy chain, hot plugging, input/outputport, peripheral. Compare ACCESS.bus.




n. The design of the bus in IBM PS/2 computers(except Models 25 and 30). The Micro Channelis electrically and physically incompatible with

the IBM PC/AT bus. Unlike the PC/AT bus, theMicro Channel functions as either a 16-bit or a32-bit bus. The Micro Channel also can bedriven independently by multiple bus masterprocessors.

PS/ 2 bus


bus

n. A set of hardware lines (conductors) used fordata transfer among the components of a

computer system. A bus is essentially a sharedhighway that connects different parts of thesystem-including the processor, disk-drivecontroller, memory, and input/output ports-andenables them to transfer information. The busconsists of specialized groups of lines that carrydifferent types of information. One group of lines carries data; another carries memoryaddresses (locations) where data items are to befound; yet another carries control signals. Busesare characterized by the number of bits they can



transfer at a single time, equivalent to thenumber of wires within the bus. A computerwith a 32-bit address bus and a 16-bit data bus,

for example, can transfer 16 bits of data at atime from any of 232 memory locations. MostPCs contain one or more expansion slots intowhich additional boards can be plugged toconnect them to the bus.

hard disk

n. A device containing one or more inflexibleplatters coated with material in which data canbe recorded magnetically, together with theirread/write heads, the head-positioningmechanism, and the spindle motor in a sealed

case that protects against outside contaminants.The protected environment allows the head tofly 10 to 25 millionths of an inch above thesurface of a platter rotating typically at 3,600 to7,200 rpm; therefore, much more data can bestored and accessed much more quickly than ona floppy disk. Most hard disks contain from twoto eight platters. Also called hard disk drive.Compare floppy disk .

soft copy




hard copyn. Printed output on paper, film, or otherpermanent medium. Compare soft copy.

URL

n. Acronym for Uniform R esource Locator. An

address for a resource on the Internet. URLs areused by Web browsers to locate Internetresources. A URL specifies the protocol to beused in accessing the resource (such as http: fora World Wide Web page or ftp: for an FTP site),the name of the server on which the resource

resides (such as //www.whitehouse.gov), and,optionally, the path to a resource (such as anHTML document or a file on that server). See


HDSL

n. Acronym for H igh-bit-rate D igital SubscriberL ine. A form of DSL, HDSL is a protocol fordigital transmission of data over standard



copper telecommunications lines (as opposed tofiber-optic lines) at rates of 1.544 Mbps in bothdirections. Also called High-data-rate Digital

Subscriber Line. See also DSL.

broadband

adj. Of or relating to communications systems inwhich the medium of transmission (such as awire or fiber-optic cable) carries multiple

messages at a time, each message modulatedon its own carrier frequency by means of modems. Broadband communication is found inwide area networks. Compare baseband.

8JAN06


n. The use of light and of light-transmittingtechnology, such as optical fibers and lasers, insending and receiving data, images, or sound.

n. A disk drive that reads and often can write

data on optical (compact) discs. Examples of optical drives include CD-ROM drives and WORMdisk drives. See also CD-ROM drive, compactdisc, WORM.



optical fiber

n. A thin strand of transparent material used to

carry optical signals. Optical fibers areconstructed from special kinds of glass andplastic, and they are designed so that a beam of light introduced at one end will remain withinthe fiber, reflecting off the inner surfaces as ittravels down the length of the fiber. Opticalfibers are inexpensive, compact, and lightweightand are often packaged many hundred to asingle cable. See also fiber optics.

optical mouse

n. A type of mouse that uses a pair of light-emitting diodes (LEDs) and a special reflective

grid pad to detect motion. The two lights are of different colors, and the special mouse pad hasa grid of lines in the same colors, one color forvertical lines and another for horizontal lines.Light detectors paired with the LEDs sense whena colored light passes over a line of the same

color, indicating the direction of movement. See also mouse. Compare mechanical mouse,optomechanical mouse.

fiber optics





strands of glass or other transparent material,with dozens or hundreds of strands housed in asingle cable. Optical fibers are essentiallyimmune to electromagnetic interference. See also optical fiber.

mechanical mouse






voice recognition



request or a statement can be made, is moredifficult, although advances are being made inthis area. Also called speech recognition. See also artificial intelligence, dictation software,neural network .

neural network







pattern recognition



thumbnail





25jan06digital signal processor

n. An integrated circuit designed for high-speeddata manipulation and used in audio,communications, image manipulation, and other


hardware

n. The physical components of a computersystem, including any peripheral equipment suchas printers, modems, and mouse devices.Compare firmware, software

26jan06

cookie

n. 1. A block of data that a server returns to aclient in response to a request from the client.2. On the World Wide Web, a block of data thata Web server stores on a client system. When a






cache






benchmark 1




benchmark 2





2feb06

thumbnail


MP3

n. Acronym for MPEG Audio Layer-3. A digitalaudio coding scheme used in distributingrecorded music over the Internet. MP3 shrinksthe size of an audio file by a factor of 10 to 12



without seriously degrading the quality (CD-recording level) of the sound. MP3 files aregiven the file extension .mp3. Although MP3 is

part of the MPEG family, it is audio-only and isnot the same as the now-defunct MPEG-3standard

string

n. A data structure composed of a sequence of

characters usually representing human-readabletext.

array

n. In programming, a list of data values, all of the same type, any element of which can be

referenced by an expression consisting of thearray name followed by an indexing expression.

Arrays are part of the fundamentals of datastructures, which, in turn, are a majorfundamental of computer programming. See

also array element, index, record1, vector.

vector

n. 1. In mathematics and physics, a variablethat has both distance and direction. Compare scalar. 2. In computer graphics, a line drawn in



a certain direction from a starting point to anendpoint, both of whose locations are identifiedby the computer using x-y- coordinates on a grid.

Vectors are used in the output of some graphicsprograms instead of groups of dots (on paper)or pixels (on screen). See also vector graphics.3. In data structures, a one-dimensional array-aset of items arranged in a single column or row.See also array, matrix.

matrix

n. An arrangement of rows and columns usedfor organizing related items, such as numbers,dots, spreadsheet cells, or circuit elements.Matrices are used in mathematics for

manipulating rectangular sets of numbers. Incomputing and computer applications, matricesare used for the similar purpose of arrangingsets of data in table form, as in spreadsheetsand lookup tables. In hardware, matrices of dotsare used in creating characters on the screen aswell as in print (as by dot-matrix printers). Inelectronics, matrices of diodes or transistors areused to create networks of logic circuits for suchpurposes as encoding, decoding, or convertinginformation. See also grid.



grid

n. 1. Two sets of lines or linear elements at right

angles to each other. 2. A spreadsheet is a gridof rows and columns; a graphics screen is a gridof horizontal and vertical lines of pixels. 3. Inoptical character recognition, a grid is used formeasuring or specifying characters. See also Cartesian coordinates.

data stream

n. An undifferentiated, byte-by-byte flow of data.

data structure

n. An organizational scheme, such as a record orarray, that can be applied to data to facilitateinterpreting the data or performing operationson it.

byte

n. Short for b inary term. A unit of data, today

almost always consisting of 8 bits. A byte canrepresent a single character, such as a letter, adigit, or a punctuation mark. Because a byterepresents only a small amount of information,



amounts of computer memory and storage areusually given in kilobytes (1,024 bytes),megabytes (1,048,576 bytes), or gigabytes

(1,073,741,824 bytes). Abbreviation: B. See also bit, gigabyte, kilobyte, megabyte. Compare octet, word.

character

n. A letter, number, punctuation mark, or other

symbol or control code that is represented to acomputer by one unit-1 byte-of information. A character is not necessarily visible, either on thescreen or on paper; a space, for example, is asmuch a character as is the letter a or any of thedigits 0 through 9. Because computers must

manage not only so-called printable charactersbut also the look (formatting) and transfer of electronically stored information, a character canadditionally indicate a carriage return or aparagraph mark in a word-processed document.It can be a signal to sound a beep, begin a newpage, or mark the end of a file. See also ASCII,control character, EBCDIC.

assembly language



n. A low-level programming language usingabbreviations or mnemonic codes in which eachstatement corresponds to a single machine

instruction. An assembly language is translatedto machine language by the assembler and isspecific to a given processor. Advantages of using an assembly language include increasedexecution speed and direct programmerinteraction with system hardware. See also

assembler, compiler, high-level language, low-level language, machine code.

assembler

n. A program that converts assembly languageprograms, which are understandable by

humans, into executable machine language. See also assemble, assembly language, assemblylisting, compiler (definition 2), machine code.

compiler

n. 1. Any program that transforms one set of symbols into another by following a set of syntactic and semantic rules. 2. A program thattranslates all the source code of a programwritten in a high-level language into object codeprior to execution of the program. See also



syntax

n. The grammar of a language; the rules

governing the structure and content of statements. See also logic, programminglanguage, syntax error. Compare semantics (definition 1).

semantics

n. 1. In programming, the relationship betweenwords or symbols and their intended meanings.Programming languages are subject to certainsemantic rules; thus, a program statement canbe syntactically correct but semanticallyincorrect; that is, a statement can be written inan acceptable form and still convey the wrong

meaning. See also syntax. 2. In artificial-intelligence research, the capacity of a network to represent relationships among objects, ideas,or situations in a humanlike way. Compare syntax.

floating-point notation

n. A numeric format that can be used torepresent very large real numbers and verysmall real numbers. Floating-point numbers are



stored in two parts, a mantissa and anexponent. The mantissa specifies the digits inthe number, and the exponent specifies the

magnitude of the number (the position of thedecimal point). For example, the numbers314,600,000 and 0.0000451 are expressedrespectively as 3146E5 and 451E-7 in floating-point notation. Most microprocessors do notdirectly support floating-point arithmetic;

consequently, floating-point calculations areperformed either by using software or with aspecial floating-point processor. Also called exponential notation. See also fixed-pointnotation, floating-point processor, integer.


n. A number represented by a mantissa and anexponent according to a given base. Themantissa is usually a value between 0 and 1. Tofind the value of a floating-point number, thebase is raised to the power of the exponent, andthe mantissa is multiplied by the result. Ordinaryscientific notation uses floating-point numberswith 10 as the base. In a computer, the base forfloating-point numbers is usually 2.




n. An arithmetic operation performed on datastored in floating-point notation. Floating-pointoperations are used wherever numbers may

have either fractional or irrational parts, as inspreadsheets and computer-aided design (CAD).Therefore, one measure of a computer's poweris how many millions of floating-point operationsper second (MFLOPS or megaflops) it canperform. Acronym: FLOP. Also called floating-

point operation. See also floating-point notation,MFLOPS.

integer

n. 1. A positive or negative "whole" number,such as 37, -50, or 764. 2. A data type

representing whole numbers. Calculationsinvolving only integers are much faster thancalculations involving floating-point numbers, sointegers are widely used in programming forcounting and numbering purposes. Integers canbe signed (positive or negative) or unsigned(positive). They can also be described as long orshort, depending on the number of bytesneeded to store them. Short integers, stored in2 bytes, cover a smaller range of numbers (forexample, -32,768 through 32,767) than do long



integers (for example, -2,147,483,648 through2,147,483,647), which are stored in 4 bytes. Also called integral number. See also floating-

point notatio



PU cache

n. A section of fast memory linking the CPU

(central processing unit) and main memory thattemporarily stores data and instructions the CPUneeds to execute upcoming commands andprograms. Considerably faster than mainmemory, the CPU cache contains data that istransferred in blocks, thereby speedingexecution. The system anticipates the data it willneed through algorithms. Also called cachememory, memory cache. See also cache, CPU,

VCACHE.

CPU

n. Acronym for central processing unit. The

computational and control unit of a computer.The CPU is the device that interprets andexecutes instructions. Mainframes and earlyminicomputers contained circuit boards full of integrated circuits that implemented the CPU.Single-chip central processing units, called

microprocessors, made possible personalcomputers and workstations. Examples of single-chip CPUs are the Motorola 68000, 68020,and 68030 chips and the Intel 8080, 8086,80286, 80386, and i486 chips. The CPU-or



microprocessor, in the case of a microcomputer-has the ability to fetch, decode, and executeinstructions and to transfer information to and

from other resources over the computer's maindata-transfer path, the bus. By definition, theCPU is the chip that functions as the "brain" of acomputer. In some instances, however, the termencompasses both the processor and thecomputer's memory or, even more broadly, the

main computer console (as opposed toperipheral equipment). See also microprocessor.

microprocessor

n. A central processing unit (CPU) on a singlechip. A modern microprocessor can have several

million transistors in an integrated-circuitpackage that can easily fit into the palm of one'shand. Microprocessors are at the heart of allpersonal computers. When memory and powerare added to a microprocessor, all the pieces,excluding peripherals, required for a computerare present. The most popular lines of microprocessors today are the 680x0 familyfrom Motorola, which powers the AppleMacintosh line, and the 80x86 family from Intel,which is at the core of all IBM PC-compatible



computers. See also 6502, 65816, 6800, 68000,68020, 68030, 68040, 80286, 80386DX,80386SX, 8080, 8086, 8088, 88000, DECchip

21064, i486DX, i486DX2, i486SL, i486SX,Pentium, PowerPC, SPARC, Z80.

FromOtherFileSunday, February 17, 2008

spam1

n. An unsolicited e-mail message sent to many recipients at one

time, or a news article posted simultaneously to many newsgroups.Spam is the electronic equivalent of junk mail. In most cases, the

content of a spam message or article is not relevant to the topic of

the newsgroup or the interests of the recipient; spam is an abuse of

the Internet in order to distribute a message (usually commercial or

religious) to a huge number of people at minimal cost.

spam2

vb. To distribute unwanted, unrequested mail widely on theInternet by posting a message to too many recipients or too many

newsgroups. The act of distributing such mail, known as

spamming, angers most Internet users and has been known to

invite retaliation, often in the form of return spamming that can

flood and possibly disable the electronic

CPU cache

n. A section of fast memory linking the CPU (central processing

unit) and main memory that temporarily stores data and

instructions the CPU needs to execute upcoming commands and

programs. Considerably faster than main memory, the CPU cache

contains data that is transferred in blocks, thereby speeding

execution. The system anticipates the data it will need through



algorithms. Also called cache memory, memory cache. See also

cache, CPU, VCACHE.

CPU

n. Acronym for central processing unit. The computational and

control unit of a computer. The CPU is the device that interprets

and executes instructions. Mainframes and early minicomputers

contained circuit boards full of integrated circuits that implemented

the CPU. Single-chip central processing units, called

microprocessors, made possible personal computers and

workstations. Examples of single-chip CPUs are the Motorola

68000, 68020, and 68030 chips and the Intel 8080, 8086, 80286,

80386, and i486 chips. The CPU-or microprocessor, in the case of

a microcomputer-has the ability to fetch, decode, and execute

instructions and to transfer information to and from other resources

over the computer's main data-transfer path, the bus. By definition,

the CPU is the chip that functions as the "brain" of a computer. In

some instances, however, the term encompasses both the processor

and the computer's memory or, even more broadly, the main

computer console (as opposed to peripheral equipment). See also

microprocessor.

microprocessor

n. A central processing unit (CPU) on a single chip. A modern

microprocessor can have several million transistors in an

integrated-circuit package that can easily fit into the palm of one's

hand. Microprocessors are at the heart of all personal computers.

When memory and power are added to a microprocessor, all the

pieces, excluding peripherals, required for a computer are present.The most popular lines of microprocessors today are the 680x0

family from Motorola, which powers the Apple Macintosh line,

and the 80x86 family from Intel, which is at the core of all IBM

PC-compatible computers. See also 6502, 65816, 6800, 68000,

68020, 68030, 68040, 80286, 80386DX, 80386SX, 8080, 8086,



8088, 88000, DECchip 21064, i486DX, i486DX2, i486SL,

i486SX, Pentium, PowerPC, SPARC, Z80.


n. An Intel chip that handles interrupt requests (IRQs). IBM AT

machines use two programmable interrupt controllers to

accommodate a maximum of 15 IRQs. The programmable

interrupt controller has been replaced by the advanced

programmable interrupt controller (APIC), which supports

multiprocessing. Acronym: PIC. See also IBM AT, IRQ.

packet

n. 1. A unit of information transmitted as a whole from one device

to another on a network. 2. In packet-switching networks, a

transmission unit of fixed maximum size that consists of binary

digits representing both data and a header containing an

identification number, source and destination addresses, and

sometimes error-control data. See also packet switching.

packet switching

n. A message-delivery technique in which small units of

information (packets) are relayed through stations in a computer

network along the best route available between the source and the

destination. A packet-switching network handles information in

small units, breaking long messages into multiple packets before

routing. Although each packet may travel along a different path,

and the packets composing a message may arrive at different times

or out of sequence, the receiving computer reassembles the originalmessage correctly. Packet-switching networks are considered to be

fast and efficient. To manage the tasks of routing traffic and

assembling/disassembling packets, such a network requires some

intelligence from the computers and software that control delivery.

The Internet is an example of a packet-switching network.



Standards for packet switching on networks are documented in the

-ITU recommendation X.25. Compare circuit switching.

circuit switching

n. A method of opening communications lines, as through the

telephone system, by creating a physical link between the initiating

and receiving parties. In circuit switching, the connection is made

at a switching center, which physically connects the two parties

and maintains an open line between them for as long as needed.

Circuit switching is typically used on the dial-up telephone

network, and it is also used on a smaller scale in privately

maintained communications networks. Unlike other methods of

transmission, such as packet switching, it requires the link to be

established before any communication can take place. Compare

message switching, packet switching

guru

n. A technical expert who is available to help solve problems and

to answer questions in an intelligible way. See also techie, wizard

(definition 1).

techie

n. A technically oriented person. Typically, a techie is the person

on whom a user calls when something breaks or the user cannot

understand a technical problem. A techie may be an engineer or a

technician, but not all engineers are techies. See also guru

wizard

n. 1. Someone who is adept at making computers perform their

"magic". A wizard is an outstanding and creative programmer or a

power user. Compare guru, UNIX wizard. 2. A participant in a



multiuser dungeon (MUD) who has permission to control the

domain, even to delete other players' characters. See also MUD. 3.

An interactive help utility within an application that guides the user

through each step of a particular task, such as starting up a word

processing document in the correct format for a business letter.

WYSBYGI

adj. Acronym for What You See Before You Get It. Providing a

preview of the effects of the changes the user has selected before

the changes are finally applied. For example, a dialog box in a

word processing program might display a sample of the font a user

has chosen before the font is actually changed in the document.

The user can cancel any changes after previewing them, and the

document will be unaffected. See also WYSIWYG.

WYSIWYG

adj. Acronym for What You See Is What You Get. Allowing a user

to view a document as it will appear in the final product, and to

directly edit the text, graphics, or other elements within that view.

A WYSIWYG language is often easier to use than a markuplanguage, which provides no immediate visual feedback regarding

the changes being made. Compare markup language

markup language

n. A set of codes in a text file that instruct a computer how to

format it on a printer or video display or how to index and link its

contents. Examples of markup languages are Hypertext Markup

Language (HTML) and Extensible Markup Language (XML),which are used in Web pages, and Standard Generalized Markup

Language (SGML), which is used for typesetting and desktop

publishing purposes and in electronic documents. Markup

languages of this sort are designed to enable documents and other



files to be platform-independent and highly portable between

applications. See also HTML, SGML, XML.

interface

n. 1. The point at which a connection is made between two

elements so that they can work with each other or exchange

information. 2. Software that enables a program to work with the

user (the user interface, which can be a command-line interface,

menu-driven, or a graphical user interface), with another program

such as the operating system, or with the computer's hardware. See

also application programming interface, graphical user interface. 3.

A card, plug, or other device that connects pieces of hardware with

the computer so that information can be moved from place to

place. For example, standardized interfaces such as RS-232-C

standard and SCSI enable communications between computers and

printers or disks. See also RS-232-C standard, SCSI.

proxy server

n. A firewall component that manages Internet traffic to and from a

local area network (LAN) and can provide other features, such asdocument caching and access control. A proxy server can improve

performance by supplying frequently requested data, such as a

popular Web page, and can filter and discard requests that the

owner does not consider appropriate, such as requests for

unauthorized access to proprietary files. See also firewall.

proxy

n. A computer (or the software that runs on it) that acts as a barrierbetween a network and the Internet by presenting only a single

network address to external sites. By acting as a go-between

representing all internal computers, the proxy protects network

identities while still providing access to the Internet. See also

proxy server.



.pdf

n. The file extension that identifies documents encoded in the

Portable Document Format developed by Adobe Systems. In order

to display or print a .pdf file, the user should obtain the freewareAdobe Acrobat Reader. See also Acrobat, Portable Document

Format

Portable Document Format

n. The Adobe specification for electronic documents that use the

Adobe Acrobat family of servers and readers. Acronym: PDF. See

also Acrobat, .pdf .

portable language

n. A language that runs in the same way on different systems and

therefore can be used for developing software for all of them. C,

FORTRAN, and Ada are portable languages because their

implementations on different systems are highly uniform;

assembly language is extremely nonportable.

27octo05

Simple Mail Transfer Protocol

n. A TCP/IP protocol for sending messages from one computer to

another on a network. This protocol is used on the Internet to route

e-mail. Acronym: SMTP. See also communications protocol,

TCP/IP. Compare CCITT X series, Post Office Protocol.

snail mail

n. A popular phrase on the Internet for referring to mail services

provided by the U.S. Postal Service and similar agencies in other

countries. The term has its origins in the fact that regular postal

mail is slow compared with e-mail.



24 MAY 2006


n. Memory access that does not involve the microprocessor and isfrequently used for data transfer directly between memory and an


n. An object-oriented version of the C programming language,

developed by Bjarne Stroustrup in the early 1980s at Bell

Laboratories and adopted by a number of vendors, including Apple

Computer and Sun Microsystems, Inc. See also C, Objective-C,

object-oriented programming.



n. In programming, a data set defined by the programmer in terms

of the information it can contain and the operations that can be

performed with it. An abstract data type is more generalized than a

data type constrained by the properties of the objects it contains-for

example, the data type "pet" is more generalized than the datatypes "pet dog," "pet bird," and "pet fish." The standard example

used in illustrating an abstract data type is the stack", a small

portion of memory used to store information, generally on a

temporary basis. As an abstract data type, the stack is simply a

structure onto which values can be pushed (added) and from which

they can be popped (removed). The type of value, such as integer,

is irrelevant to the definition.

The way in which the program performs operations on abstract

data types is encapsulated, or hidden, from the rest of the program.

Encapsulation enables the programmer to change the definition of

the data type or its operations without introducing errors to the

existing code that uses the abstract data type. Abstract data types



represent an intermediate step between traditional programming

and object-oriented programming. See also data type, object-

oriented programming.

encapsulation

n. In object-oriented programming, the packaging of attributes

(properties) and functionality (methods or behaviors) to create an

object that is essentially a black box—one whose internal structure

remains private and whose services can be accessed by other

objects only through messages passed via a clearly defined

interface (the programming equivalent of a mailbox or telephone

line). Encapsulation ensures that the object providing service can

prevent other objects from manipulating its data or procedures

directly, and it enables the object requesting service to ignore the

details of how that service is provided. See also information

hiding.

fuzzy logic

n. A form of logic used in some expert systems and other artificial-

intelligence applications in which variables can have degrees of truthfulness or falsehood represented by a range of values between

1 (true) and 0 (false). With fuzzy logic, the outcome of an

operation can be expressed as a probability rather than as a

certainty. For example, an outcome might be probably true,

possibly true, possibly false, or probably false. See also expert

system.

expert system/ 2dec04

n. An application program that makes decisions or solves problems

in a particular field, such as finance or medicine, by using

knowledge and analytical rules defined by experts in the field. It

uses two components, a knowledge base and an inference engine,

to form conclusions. Additional tools include user interfaces and



explanation facilities, which enable the system to justify or explain

its conclusions as well as allowing developers to run checks on the

operating system. See also artificial intelligence, inference engine,

intelligent database, encapsulation

n. In object-oriented programming, the packaging of attributes

(properties) and functionality (methods or behaviors) to create an

object that is essentially a black box—one whose internal structure

remains private and whose services can be accessed by other

objects only through messages passed via a clearly defined

interface (the programming equivalent of a mailbox or telephone

line). Encapsulation ensures that the object providing service can

prevent other objects from manipulating its data or proceduresdirectly, and it enables the object requesting service to ignore the

details of how that service is provided. See also information

hiding.

black box

n. A unit of hardware or software whose internal structure is

unknown but whose function is documented. The internal

mechanics of the function do not matter to a designer who uses ablack box to obtain that function. For example, a memory chip can

be viewed as a black box. Many people use memory chips and

design them into computers, but generally only memory chip

designers need to understand their internal operation.

encapsulate

vb. 1. To treat a collection of structured information as a whole

without affecting or taking notice of its internal structure. Incommunications, a message or packet constructed according to one

protocol, such as a TCP/IP packet, may be taken with its

formatting data as an undifferentiated stream of bits that is then

broken up and packaged according to a lower-level protocol (for

example, as ATM packets) to be sent over a particular network; at



the destination, the lower-level packets are assembled, re-creating

the message as formatted for the encapsulated protocol. See also

ATM (definition 1). 2. In object-oriented programming, to keep the

implementation details of a class a separate file whose contents do

not need to be known by a programmer using that class. See alsoobject-oriented programming, TCP/IP.


sensor



sensor glove




transducer

n. A device that converts one form of energy into another. Electronic transducers either

convert electric energy to another form of energy or convert nonelectric to electric

energy.

virtual reality





information hiding



n. A design practice in which implementation details for both data

structures and algorithms within a module or subroutine are hidden

from routines using that module or subroutine, so as to ensure that

those routines do not depend on some particular detail of the

implementation. In theory, information hiding allows the moduleor subroutine to be changed without breaking the routines that use

it. See also break , module, routine, subroutine.

module

n. 1. In programming, a collection of routines and data structures

that performs a particular task or implements a particular abstract

data type. Modules usually consist of two parts: an interface, which

lists the constants, data types, variables, and routines that can be

accessed by other modules or routines, and an implementation,

which is private (accessible only to the module) and which

contains the source code that actually implements the routines in

the module. See also abstract data type, information hiding,

Modula-2, modular programming. 2. In hardware, a self-contained

component that can provide a complete function to a system and

can be interchanged with other modules that provide similar

functions. See also memory card, SIMM.

interface

n. 1. The point at which a connection is made between two

elements so that they can work with each other or exchange

information. 2. Software that enables a program to work with the

user (the user interface, which can be a command-line interface,

menu-driven, or a graphical user interface), with another program

such as the operating system, or with the computer's hardware. Seealso application programming interface, graphical user interface. 3.

A card, plug, or other device that connects pieces of hardware with

the computer so that information can be moved from place to

place. For example, standardized interfaces such as RS-232-C



standard and SCSI enable communications between computers and

printers or disks. See also RS-232-C standard, SCSI.


n. A set of routines used by an application program to direct the

performance of procedures by the computer's operating system.

Acronym: API. Also called application program interface.


n. A visual computer environment that represents programs, files,

and options with graphical images, such as icons, menus, and

dialog boxes on the screen. The user can select and activate theseoptions by pointing and clicking with a mouse or, often, with the

keyboard. A particular item (such as a scroll bar) works the same

way to the user in all applications, because the graphical user

interface provides standard software routines to handle these

elements and report the user's actions (such as a mouse click on a

particular icon or at a particular location in text, or a key press);

applications call these routines with specific parameters rather than

attempting to reproduce them from scratch. Acronym: GUI.

operating system

n. The software that controls the allocation and usage of hardware

resources such as memory, central processing unit (CPU) time,

disk space, and peripheral devices. The operating system is the

foundation software on which applications depend. Popular

operating systems include Windows 98, Windows NT, Mac OS,

and UNIX. Acronym: OS. Also called executive.

virtual

adj. Of or pertaining to a device, service, or sensory input that is

perceived to be what it is not in actuality, usually as more "real" or

concrete than it actually is.



polymorphism

n. In an object-oriented programming language, the ability to

redefine a routine in a derived class (a class that inherited its data

structures and routines from another class). Polymorphism allowsthe programmer to define a base class that includes routines that

perform standard operations on groups of related objects, without

regard to the exact type of each object. The programmer then

redefines the routines in the derived class for each type, taking into

account the characteristics of the object. See also class, derived

class, object (definition 2), object-oriented programming.


n. An Intel chip that handles interrupt requests (IRQs). IBM AT

machines use two programmable interrupt controllers to

accommodate a maximum of 15 IRQs. The programmable

interrupt controller has been replaced by the advanced

programmable interrupt controller (APIC), which supports

multiprocessing. Acronym: PIC. See also IBM AT, IRQ

spam

1


time, or a news article posted simultaneously to many newsgroups.

Spam is the electronic equivalent of junk mail. In most cases, the





spam2

vb. To distribute unwanted, unrequested mail widely on the

Internet by posting a message to too many recipients or too many






flood and possibly disable the electronic mailbox of the original

spammer.

31dec05

filter

n. 1. A program or set of features within a program that reads its

standard or designated input, transforms the input in some desired

way, and then writes the output to its standard or designated output

destination. A database filter, for example, might flag information

of a certain age. 2. In communications and electronics, hardware orsoftware that selectively passes certain elements of a signal and

eliminates or minimizes others. A filter on a communications

network, for example, must be designed to transmit a certain

frequency but attenuate (dampen) frequencies above it (a lowpass

filter), those below it (a highpass filter), or those above and below

it (a bandpass filter). 3. A pattern or mask through which data is

passed to weed out specified items. For instance, a filter used in e-

mail or in retrieving newsgroup messages can allow users to filterout messages from other users. See also e-mail filter, mask . 4. In

computer graphics, a special effect or production effect that is

applied to bitmapped images; for example, shifting pixels within

an image, making elements of the image transparent, or distorting

the image. Some filters are built into a graphics program, such as a

paint program or an image editor. Others are separate software

packages that plug into the graphics program. See also bitmapped

graphics, image editor, paint program.

e-mail filter

n. A feature in e-mail-reading software that automatically sorts

incoming mail into different folders or mailboxes based on

information contained in the message. For example, all incoming



mail from a user's Uncle Joe might be placed in a folder labeled

"Uncle Joe". Filters may also be used either to block or accept e-

mail from designated sources.

n. Short for picture (pix) element. One spot in a rectilinear grid of thousands of such spots that are individually "painted" to form an

image produced on the screen by a computer or on paper by a

printer. A pixel is the smallest element that display or print

hardware and software can manipulate in creating letters, numbers,

or graphics. Also called pel.

pixel image

n. The representation of a color graphic in a computer's memory. Apixel image is similar to a bit image, which also describes a screen

graphic, but a pixel image has an added dimension, sometimes

called depth, that describes the number of bits in memory assigned

to each on-screen pixel.

pixel map

n. A data structure that describes the pixel image of a graphic,

including such features as color, image, resolution, dimensions,

storage format, and number of bits used to describe each pixel. See

also pixel, pixel image.

31dec05

BIOS

n. Acronym for basic input/output system. On PC-compatible

computers, the set of essential software routines that tests hardware

at startup, starts the operating system, and supports the transfer of

data among hardware devices. The BIOS is stored in read-only

memory (ROM) so that it can be executed when the computer is

turned on. Although critical to performance, the BIOS is usually



invisible to computer users. See also AMI BIOS, CMOS setup,

Phoenix BIOS, ROM BIOS. Compare Toolbox.

flip-flop

n. A circuit that alternates between two possible states when a

pulse is received at the input. For example, if the output of a flip-

flop is high and a pulse is received at the input, the output "flips"

to low; a second input pulse "flops" the output back to high, and so

on. Also called bistable multivibrator

float

n. The data type name used in some programming languages,notably C, to declare variables that can store floating-point

numbers. See also data type, floating-point number, variable


n. A number represented by a mantissa and an exponent according

to a given base. The mantissa is usually a value between 0 and 1.

To find the value of a floating-point number, the base is raised to

the power of the exponent, and the mantissa is multiplied by theresult. Ordinary scientific notation uses floating-point numbers

with 10 as the base. In a computer, the base for floating-point

numbers is usually 2.


n. An arithmetic operation performed on data stored in floating-

point notation. Floating-point operations are used wherever

numbers may have either fractional or irrational parts, as in

spreadsheets and computer-aided design (CAD). Therefore, one

measure of a computer's power is how many millions of floating-

point operations per second (MFLOPS or megaflops) it can

perform. Acronym: FLOP. Also called floating-point operation.

See also floating-point notation, MFLOfloating-point notation



2,147,483,647), which are stored in 4 bytes. Also called integral

number. See also floating-point notation

byte

n. Short for binary term. A unit of data, today almost always

consisting of 8 bits. A byte can represent a single character, such as

a letter, a digit, or a punctuation mark. Because a byte represents

only a small amount of information, amounts of computer memory

and storage are usually given in kilobytes (1,024 bytes), megabytes

(1,048,576 bytes), or gigabytes (1,073,741,824 bytes).

Abbreviation: B. See also bit, gigabyte, kilobyte, megabyte.

Compare octet, word.

character

n. A letter, number, punctuation mark, or other symbol or control

code that is represented to a computer by one unit-1 byte-of

information. A character is not necessarily visible, either on the

screen or on paper; a space, for example, is as much a character as

is the letter a or any of the digits 0 through 9. Because computers

must manage not only so-called printable characters but also thelook (formatting) and transfer of electronically stored information,

a character can additionally indicate a carriage return or a

paragraph mark in a word-processed document. It can be a signal

to sound a beep, begin a new page, or mark the end of a file. See

also ASCII, control character, EBCDIC.

nibble or nybble


ascii

n. In an FTP client program, the command that instructs the FTP

server to send or receive files as ASCII text. See also ASCII, FTP

client Compare binary2



ASCII

n. Acronym for American Standard Code for Information

Interchange. A coding scheme using 7 or 8 bits that assigns

numeric values to up to 256 characters, including letters, numerals,punctuation marks, control characters, and other symbols. ASCII

was developed in 1968 to standardize data transmission among

disparate hardware and software systems and is built into most

minicomputers and all PCs. ASCII is divided into two sets: 128

characters (standard ASCII) and an additional 128 (extended

ASCII). See also ASCII file, character, character code, control

character, extended ASCII, standard ASCII. Compare EBCDIC.

EBCDIC.

ASCII character set

n. A standard 7-bit code for representing ASCII characters using

binary values; code values range from 0 to 127. Most PC-based

systems use an 8-bit extended ASCII code, with an extra 128

characters used to represent special symbols, foreign-language

characters, and graphic symbols. See also ASCII, character,EBCDIC, extended ASCII, standard ASCII.

extended ASCII

n. Any set of characters assigned to ASCII values between decimal

128 and 255 (hexadecimal 80 through FF). The specific characters

assigned to the extended ASCII codes vary between computers and

between programs, fonts, or graphics characters. Extended ASCII

adds capability by allowing for 128 additional characters, such asaccented letters, graphics characters, and special symbols. See also

ASCII.

C++



n. An object-oriented version of the C programming language,

developed by Bjarne Stroustrup in the early 1980s at Bell

Laboratories and adopted by a number of vendors, including Apple

Computer and Sun Microsystems, Inc. See also C, Objective-C,

object-oriented programming.


n. A programming paradigm in which a program is viewed as a

collection of discrete objects that are self-contained collections of

data structures and routines that interact with other objects.

Acronym: OOP. See also C++, object (definition 2), Objective-C.


n. A programming paradigm in which a program is viewed as a

collection of discrete objects that are self-contained collections of

data structures and routines that interact with other objects.

Acronym: OOP. See also C++, object (definition 2), Objective-C.

object

n. 1. Short for object code (machine-readable code). 2. In object-oriented programming, a variable comprising both routines and

data that is treated as a discrete entity. See also abstract data type,

module (definition 1), object-oriented programming. 3. In

graphics, a distinct entity. For example, a bouncing ball might be

an object in a graphics program.

module

n. 1. In programming, a collection of routines and data structures

that performs a particular task or implements a particular abstract

data type. Modules usually consist of two parts: an interface, which

lists the constants, data types, variables, and routines that can be

accessed by other modules or routines, and an implementation,

which is private (accessible only to the module) and which



contains the source code that actually implements the routines in

the module. See also abstract data type, information hiding,

Modula-2, modular programming. 2. In hardware, a self-contained

component that can provide a complete function to a system and

can be interchanged with other modules that provide similarfunctions. See also memory card, SIMM.

abstract data type

n. In programming, a data set defined by the programmer in terms

of the information it can contain and the operations that can be

performed with it. An abstract data type is more generalized than a

data type constrained by the properties of the objects it contains-for

example, the data type "pet" is more generalized than the data

types "pet dog," "pet bird," and "pet fish." The standard example

used in illustrating an abstract data type is the stack", a small

portion of memory used to store information, generally on a

temporary basis. As an abstract data type, the stack is simply a

structure onto which values can be pushed (added) and from which

they can be popped (removed). The type of value, such as integer,

is irrelevant to the definition.

The way in which the program performs operations on abstract

data types is encapsulated, or hidden, from the rest of the program.

Encapsulation enables the programmer to change the definition of

the data type or its operations without introducing errors to the

existing code that uses the abstract data type. Abstract data types

represent an intermediate step between traditional programming

and object-oriented programming. See also data type, object-


data type

n. In programming, a definition of a set of data that specifies the

possible range of values of the set, the operations that can be

performed on the values, and the way in which the values are



stored in memory. Defining the data type allows a computer to

manipulate the data appropriately. Data types are most often

supported in high-level languages and often include types such as

real, integer, floating point, character, Boolean, and pointer. How a

language handles data typing is one of its major characteristics.See also cast, constant, enumerated data type, strong typing, type

checking, user-defined data type, variable, weak typing.

toolbox

n. A set of predefined (and usually precompiled) routines a

programmer can use in writing a program for a particular machine,

environment, or application. Also called toolkit. See also library

(definition 1).

Toolbox

n. A set of routines stored mostly in the read-only memory of a

Macintosh that provides application programmers with the tools

needed to support the graphical interface characteristic of the

computer. Also called User Interface Toolbox.

disk drive

n. An electromechanical device that reads from and writes to disks.

The main components of a disk drive include a spindle on which

the disk is mounted, a drive motor that spins the disk when the

drive is in operation, one or more read/write heads, a second motor

that positions the read/write head(s) over the disk, and controllercircuitry that synchronizes read/write activities and transfers

information to and from the computer. Two types of disk drives are

in common use: floppy disk drives and hard disk drives. Floppy

disk drives are designed to accept removable disks in either 5.25-



inch or 3.5-inch format; hard disk drives are faster, high-capacity

storage units that are completely enclosed in a protective case.

paradigm

n. An archetypal example or pattern that provides a model for a

process or system

architecture

n. 1. The physical construction or design of a computer system and

its components. See also cache, CISC, closed architecture, network

architecture, open architecture, pipelining, RISC. 2. The data-

handling capacity of a microprocessor. 3. The design of applicationsoftware incorporating protocols and the means for expansion and

interfacing with other programs.

cache

\kash\ n. A special memory subsystem in which frequently used

data values are duplicated for quick access. A memory cache stores

the contents of frequently accessed RAM locations and the

addresses where these data items are stored. When the processorreferences an address in memory, the cache checks to see whether

it holds that address. If it does hold the address, the data is returned

to the processor; if it does not, a regular memory access occurs. A

cache is useful when RAM accesses are slow compared with the

microprocessor speed, because cache memory is always faster than

main RAM memory. See also disk cache, wait state.

disk

n. 1. A round, flat piece of flexible plastic coated with a magnetic

material that can be electrically influenced to hold information

recorded in digital (binary) form and encased in a protective plastic

jacket to protect them from damage and contamination. Also called



floppy, floppy disk, microfloppy disk. Compare compact disc,

disc. 2. See hard drive

compact disc

n. 1. An optical storage medium for digital data, usually audio. A

compact disc is a nonmagnetic, polished metal disc with a

protective plastic coating that can hold up to 74 minutes of high-

fidelity recorded sound. The disk is read by an optical scanning

mechanism that uses a high-intensity light source, such as a laser,

and mirrors. Also called optical disc. 2. A technology that forms

the basis of media such as CD-ROM, CD-ROM/XA, CD-I, CD-R,

DVI, and PhotoCD. These media are all compact disc-based but

store various types of digital information and have different

read/write capabilities. Documentation for compact disc formats

can be found in books designated by the color of their covers. For

example, documentation for audio compact discs is found in the

Red Book. See also CD-I, CD-R, CD-ROM, CD-ROM/XA, DVI,

Green Book (definition 2), Orange Book (definition 2), PhotoCD,

Red Book (definition 2). 3. See CD.

disc

n. A round, flat piece of nonmagnetic, shiny metal encased in a

plastic coating, designed to be read from and written to by optical

(laser) technology. It is now standard practice to use the spelling

disc for optical discs and disk in all other computer contexts, such

as floppy disk, hard disk, and RAM disk. See also compact disc.

RS-232-C standard

n. An accepted industry standard for serial communications

connections. Adopted by the Electrical Industries Association, this

Recommended Standard (RS) defines the specific lines and signal

characteristics used by serial communications controllers to

standardize the transmission of serial data between devices. The



letter C denotes that the current version of the standard is the third

in a series. See also CTS, DSR, DTR, RTS, RXD, TXD.


n. Processing that involves the more or less continuous

participation of the user. Such a command/response mode is

characteristic of microcomputers. Compare batch processing

(definition 2).

interactive program

n. A program that exchanges output and input with the user, who

typically views a display of some sort and uses an input device,such as a keyboard, mouse, or joystick, to provide responses to the

program. A computer game is an interactive program. Compare

batch program.

handshake

n. A series of signals acknowledging that communication or the

transfer of information can take place between computers or other

devices. A hardware handshake is an exchange of signals overspecific wires (other than the data wires), in which each device

indicates its readiness to send or receive data. A software

handshake consists of signals transmitted over the same wires used

to transfer data, as in modem-to-modem communications over

telephone lines.

31dec05


n. A set of rules or standards designed to enable computers to

connect with one another and to exchange information with as little

error as possible. The protocol generally accepted for standardizing

overall computer communications is a seven-layer set of hardware



and software guidelines known as the OSI (Open Systems

Interconnection) model. A somewhat different standard, widely

used before the OSI model was developed, is IBM's SNA (Systems

Network Architecture). The word protocol is often used,

sometimes confusingly, in reference to a multitude of standardsaffecting different aspects of communication, such as file transfer

(for example, XMODEM and ZMODEM), handshaking (for

example, XON/XOFF), and network transmissions (for example,

CSMA/CD). See also ISO/OSI model, SNA.

TCP/IP

n. Acronym for Transmission Control Protocol/Internet Protocol.

A protocol suite (or set of protocols) developed by the Department

of Defense for communications over interconnected, sometimes

dissimilar, networks. It is built into the UNIX system and has

become the de facto standard for data transmission over networks,

including the Internet

1jan2006

spam

1


time, or a news article posted simultaneously to many newsgroups.

Spam is the electronic equivalent of junk mail. In most cases, the





spam2

vb. To distribute unwanted, unrequested mail widely on the

Internet by posting a message to too many recipients or too many






flood and possibly disable the electronic mailbox of the original

spammer

6jan06

ADSL

n. Acronym for asymmetric digital subscriber line. Technology and

equipment allowing high-speed digital communication, including

video signals, across an ordinary twisted-pair copper phone line,

with speeds up to 8 Mbps (megabits per second) downstream (to

the customer) and up to 640 Kbps (kilobits per second) upstream.ADSL access to the Internet is offered by some regional telephone

companies, offering users faster connection times than those

available through connections made over standard phone lines.

Also called asymmetric digital subscriber loop. Compare SDSL.

SDSL

n. Acronym for symmetric (or single-line) digital subscriber line, a

digital telecommunications technology that is a variation of HDSL.

SDSL uses one pair of copper wire rather than two pairs of wires

and transmits at 1.544 Mbps. Compare ADSL.

VoIP

n. Acronym for Voice over IP. The use of the Internet Protocol (IP)

for transmitting voice communications. VoIP delivers digitized

audio in packet form and can be used for transmitting overintranets, extranets, and the Internet. It is essentially an

inexpensive alternative to traditional telephone communication

over the circuit-switched Public Switched Telephone Network

(PSTN). VoIP covers computer-to-computer, computer-to-

telephone, and telephone-based communications. For the sake of



compatibility and interoperability, a group called the VoIP Forum

promotes product development based on the ITU-T H.323 standard

for transmission of multimedia over the Internet. Also called

Internet telephony. See also H.323.

volatile memory

n. 1. Memory, such as RAM, that loses its data when the power is

shut off. Compare nonvolatile memory. 2. Memory used by a

program that can change independently of the program, such as

memory shared by another program or by an interrupt service

routine.

nonvolatile memory

n. A storage system that does not lose data when power is removed

from it. Intended to refer to core memory, ROM, EPROM, flash

memory, bubble memory, or battery-backed CMOS RAM, the

term is occasionally used in reference to disk subsystems as well.

See also bubble memory, CMOS RAM, core, EPROM, flash

memory, ROM.

flash memory

n. A type of nonvolatile memory. Flash memory is similar to

EEPROM memory in function but it must be erased in blocks,

whereas EEPROM can be erased one byte at a time. Because of its

block-oriented nature, flash memory is commonly used as a

supplement to or replacement for hard disks in portable computers.

In this context, flash memory either is built into the unit or, more

commonly, is available as a PC Card that can be plugged into aPCMCIA slot. A disadvantage of the block-oriented nature of flash

memory is that it cannot be practically used as main memory

(RAM) because a computer needs to be able to write to memory in

single-byte increments. See also EEPROM, nonvolatile memory,

PC Card, PCMCIA slot



IP

n. Acronym for Internet Protocol. The protocol within TCP/IP that

governs the breakup of data messages into packets, the routing of

the packets from sender to destination network and station, and thereassembly of the packets into the original data messages at the

destination. IP runs at the internetwork layer in the TCP/IP model-

equivalent to the network layer in the ISO/OSI reference model.

See also ISO/OSI reference model, TCP/IP. Compare TCP.

TCP

n. Acronym for Transmission Control Protocol. The protocol

within TCP/IP that governs the breakup of data messages intopackets to be sent via IP (Internet Protocol), and the reassembly

and verification of the complete messages from packets received

by IP. A connection-oriented, reliable protocol (reliable in the

sense of ensuring error-free delivery), TCP corresponds to the

transport layer in the ISO/OSI reference model. See also ISO/OSI

reference model, packet, TCP/IP. Compare UDP.

packet

n. 1. A unit of information transmitted as a whole from one device

to another on a network. 2. In packet-switching networks, a

transmission unit of fixed maximum size that consists of binary

digits representing both data and a header containing an

identification number, source and destination addresses, and

sometimes error-control data. See also packet switching.

USB

n. Acronym for universal serial bus. A serial bus with a data

transfer rate of 12 megabits per second (Mbps) for connecting

peripherals to a microcomputer. USB can connect up to 127

peripherals, such as external CD-ROM drives, printers, modems,



mice, and keyboards, to the system through a single, general-

purpose port. This is accomplished by daisy chaining peripherals

together. USB is designed to support the ability to automatically

add and configure new devices and the ability to add such devices

without having to shut down and restart the system (hot plugging).USB was developed by Intel, Compaq, DEC, IBM, Microsoft,

NEC, and Northern Telecom. It competes with DEC's

ACCESS.bus for lower-speed applications. See also bus, daisy

chain, hot plugging, input/output port, peripheral. Compare

ACCESS.bus.


n. The design of the bus in IBM PS/2 computers (except Models

25 and 30). The Micro Channel is electrically and physically

incompatible with the IBM PC/AT bus. Unlike the PC/AT bus, the

Micro Channel functions as either a 16-bit or a 32-bit bus. The

Micro Channel also can be driven independently by multiple bus

master processors.

PS/2 bus


bus

n. A set of hardware lines (conductors) used for data transfer

among the components of a computer system. A bus is essentially

a shared highway that connects different parts of the system-

including the processor, disk-drive controller, memory, and

input/output ports-and enables them to transfer information. Thebus consists of specialized groups of lines that carry different types

of information. One group of lines carries data; another carries

memory addresses (locations) where data items are to be found; yet

another carries control signals. Buses are characterized by the

number of bits they can transfer at a single time, equivalent to the



number of wires within the bus. A computer with a 32-bit address

bus and a 16-bit data bus, for example, can transfer 16 bits of data

at a time from any of 232

memory locations. Most PCs contain one

or more expansion slots into which additional boards can be

plugged to connect them to the bus.

hard disk

n. A device containing one or more inflexible platters coated with

material in which data can be recorded magnetically, together with

their read/write heads, the head-positioning mechanism, and the

spindle motor in a sealed case that protects against outside

contaminants. The protected environment allows the head to fly 10

to 25 millionths of an inch above the surface of a platter rotating

typically at 3,600 to 7,200 rpm; therefore, much more data can be

stored and accessed much more quickly than on a floppy disk.

Most hard disks contain from two to eight platters. Also called

hard disk drive. Compare floppy disk .

soft copy

n. The temporary images presented on a computer display screen.Compare hard copy.

hard copy

n. Printed output on paper, film, or other permanent medium.

Compare soft copy.

URL

n. Acronym for Uniform Resource Locator. An address for a

resource on the Internet. URLs are used by Web browsers to locate

Internet resources. A URL specifies the protocol to be used in

accessing the resource (such as http: for a World Wide Web page

or ftp: for an FTP site), the name of the server on which the

resource resides (such as //www.whitehouse.gov), and, optionally,



the path to a resource (such as an HTML document or a file on that

server). See also FTP1

(definition 1), HTML, HTTP, path

(definition 1), server (definition 2), virtual path (definition 1), Web

browser.

HDSL

n. Acronym for High-bit-rate Digital Subscriber Line. A form of

DSL, HDSL is a protocol for digital transmission of data over

standard copper telecommunications lines (as opposed to fiber-

optic lines) at rates of 1.544 Mbps in both directions. Also called

High-data-rate Digital Subscriber Line. See also DSL.

broadband

adj. Of or relating to communications systems in which the

medium of transmission (such as a wire or fiber-optic cable)

carries multiple messages at a time, each message modulated on its

own carrier frequency by means of modems. Broadband

communication is found in wide area networks. Compare

baseband.

8JAN06


n. The use of light and of light-transmitting technology, such as

optical fibers and lasers, in sending and receiving data, images, or

sound.

n. A disk drive that reads and often can write data on optical

(compact) discs. Examples of optical drives include CD-ROM

drives and WORM disk drives. See also CD-ROM drive, compact

disc, WORM.

optical fiber



n. A thin strand of transparent material used to carry optical

signals. Optical fibers are constructed from special kinds of glass

and plastic, and they are designed so that a beam of light

introduced at one end will remain within the fiber, reflecting off

the inner surfaces as it travels down the length of the fiber. Opticalfibers are inexpensive, compact, and lightweight and are often

packaged many hundred to a single cable. See also fiber optics.

optical mouse

n. A type of mouse that uses a pair of light-emitting diodes (LEDs)

and a special reflective grid pad to detect motion. The two lights

are of different colors, and the special mouse pad has a grid of

lines in the same colors, one color for vertical lines and another for

horizontal lines. Light detectors paired with the LEDs sense when

a colored light passes over a line of the same color, indicating the

direction of movement. See also mouse. Compare mechanical

mouse, optomechanical mouse.

fiber optics

n. A technology for the transmission of light beams along opticalfibers. A light beam, such as that produced in a laser, can be

modulated to carry information. Because light has a higher

frequency on the electromagnetic spectrum than other types of

radiation, such as radio waves, a single fiber-optic channel can

carry significantly more information than most other means of

information transmission. Optical fibers are thin strands of glass or

other transparent material, with dozens or hundreds of strands

housed in a single cable. Optical fibers are essentially immune to

electromagnetic interference. See also optical fiber.

mechanical mouse

n. A type of mouse in which the motion of a ball on the bottom of

the mouse is translated into directional signals. As the user moves



the mouse, the ball rolls, turning a pair of wheels mounted at right

angles inside the mouse that have conductive markings on their

surfaces. Because the markings permit an electric current to flow, a

set of conductive brushes that ride on the surface of the conductive

wheels can detect these conductive markings. The electronics inthe mouse translate these electrical movement signals into mouse-

movement information that can be used by the computer. See also

mouse, trackball. Compare optical mouse, optomechanical mouse.

voice recognition

n. The capability of a computer to understand the spoken word for

the purpose of receiving commands and data input from the

speaker. Systems that can recognize limited vocabularies as spoken

by specific individuals have been developed, but developing a

system that deals with a variety of speech patterns and accents, as

well as with the various ways in which a request or a statement can

be made, is more difficult, although advances are being made in

this area. Also called speech recognition. See also artificial

intelligence, dictation software, neural network .

neural network

n. A type of artificial-intelligence system modeled after the

neurons (nerve cells) in a biological nervous system and intended

to simulate the way a brain processes information, learns, and

remembers. A neural network is designed as an interconnected

system of processing elements, each with a limited number of

inputs and an output. These processing elements are able to "learn"

by receiving weighted inputs that, with adjustment, time, and

repetition, can be made to produce appropriate outputs. Neuralnetworks are used in areas such as pattern recognition, speech

analysis, and speech synthesis. See also artificial intelligence,

pattern recognition (definition 1).

pattern recognition



digital signal processor

n. An integrated circuit designed for high-speed data manipulation

and used in audio, communications, image manipulation, and other


hardware

n. The physical components of a computer system, including any

peripheral equipment such as printers, modems, and mouse

devices. Compare firmware, software

26jan06

cookie

n. 1. A block of data that a server returns to a client in response to

a request from the client. 2. On the World Wide Web, a block of

data that a Web server stores on a client system. When a user

returns to the same Web site, the browser sends a copy of the

cookie back to the server. Cookies are used to identify users, toinstruct the server to send a customized version of the requested

Web page, to submit account information for the user, and for

other administrative purposes. 3. Originally an allusion to fortune

cookie, a UNIX program that outputs a different message, or

"fortune", each time it is used. On some systems, the cookie

program is run during user logon.

cache

\kash\ n. A special memory subsystem in which frequently used

data values are duplicated for quick access. A memory cache stores

the contents of frequently accessed RAM locations and the

addresses where these data items are stored. When the processor

references an address in memory, the cache checks to see whether



it holds that address. If it does hold the address, the data is returned

to the processor; if it does not, a regular memory access occurs. A

cache is useful when RAM accesses are slow compared with the

microprocessor speed, because cache memory is always faster than

main RAM memory. See also disk cache, wait state.

benchmark 1

n. A test used to measure hardware or software performance.

Benchmarks for hardware use programs that test the capabilities of

the equipment-for example, the speed at which a CPU can execute

instructions or handle floating-point numbers. Benchmarks for

software determine the efficiency, accuracy, or speed of a program

in performing a particular task, such as recalculating data in a

spreadsheet. The same data is used with each program tested, so

the resulting scores can be compared to see which programs

perform well and in what areas. The design of fair benchmarks is

something of an art, because various combinations of hardware and

software can exhibit widely variable performance under different

conditions. Often, after a benchmark has become a standard,

developers try to optimize a product to run that benchmark faster

than similar products run it in order to enhance sales. See alsosieve of Eratosthenes.

benchmark 2

vb. To measure the performance of hardware or software.

benign virus

n. A program that exhibits properties of a virus, such as self-replication, but does not otherwise do harm to the computer

systems that it infects.

2feb06

thumbnail



n. A miniature version of an image or electronic version of a page

that is generally used to allow quick browsing through multiple

images or pages. For example, Web pages often contain

thumbnails of images (which can be loaded much more quickly by

the Web browser than the full-size image). Many of thesethumbnails can be clicked on to load the complete version of the

image.

Java

n. An object-oriented programming language developed by Sun Microsystems. Similar to

C++, Java is smaller, more portable, and easier to use than C++ because it is more robust

and it manages memory on its own. Java was also designed to be secure and platform-

neutral (meaning that it can be run on any platform) through the fact that Java programs

are compiled into bytecode, which is not refined to the point of relying on platform-specific instructions and runs on a computer in a special software environment known as

a virtual machine. This characteristic of Java makes it a useful language for programmingWeb applications, since users access the Web from many types of computers. Java is

used in programming small applications, or applets, for the World Wide Web, as well as

in creating distributed network applications. See also bytecode, Java applet, Jini, object-


platform

n. 1. The foundation technology of a computer system. Because computers are layered

devices composed of a chip-level hardware layer, a firmware and operating-system layer,and an applications program layer, the bottommost layer of a machine is often called a

platform. 2. In everyday usage, the type of computer or operating system being used.

Code Division Multiple Access

n. A form of multiplexing in which the transmitter encodes the signal, using a pseudo-

random sequence that the receiver also knows and can use to decode the received signal.Each different random sequence corresponds to a different communication channel.

Motorola uses Code Division Multiple Access for digital cellular phones. Acronym:

CDMA. Also called spread spectrum. See also multiplexing, transmitter

multiplexing

n. A technique used in communications and input/output operations for transmitting anumber of separate signals simultaneously over a single channel or line. To maintain the

integrity of each signal on the channel, multiplexing can separate the signals by time,

space, or frequency. The device used to combine the signals is a multiplexer . See also

FDM, space-division multiplexing, time-division multiplexing



space-division multiplexing

n. The first automated form of communications multiplexing, which replaced the human-

operated switchboard. Space-division multiplexing was replaced by frequency-division

multiplexing (FDM), which was in turn replaced by time-division multiplexing (TDM).

Acronym: SDM. See also FDM, multiplexing, time-division multiplexing

TDMA

n. A multiplexing technology used to divide a single cellular phone channel into multiple

subchannels. TDMA works by allocating separate time slots to each user. It is

implemented in D-AMPS (Digital Advanced Mobile Phone Service), which relies on

TDMA to divide each of the 30 analog AMPS channels into three separate subchannels,and GSM (Global System for Mobile Communications). See also D-AMPS, Global

System for Mobile Communications. Compare AMPS, FDMA.

tear-off

Global System for Mobile Communications

n. A digital cellular telephone technology widely used throughout Europe, in Australia,

India, Africa, Asia, and the Middle East, and growing in use in the United States.

Originating in 1982 with a European study group called the Groupe Spéciale Mobile,GSM is a wireless platform based on TDMA (Time Division Multiple Access) to digitize

data; its features include not only telephony but also voice mail, call forwarding, fax,

caller ID, Internet access, and e-mail. GSM operates at three frequency ranges: 900 MHz(GSM 900) in Europe and most of the world; 1800 MHz (GSM 1800) in a number of

European countries; and 1900 MHz (GSM 1900-also called PCS 1900 or DCS 1900) inthe United States and Canada. Acronym: GSM. See also SIM card, TDMA.

spread spectrum

adj. Of or pertaining to a system of secure radio communication in which the content of a

transmission is broken into split-second pieces, which are transmitted over separatefrequencies. When a receiver identifies a spread spectrum signal, it reassembles it to its

original form. Spread spectrum was invented by the actress Hedy Lamarr in 1940, but it

was not used until 1962.

word

n. The native unit of storage on a particular machine. A word is the largest amount of

data that can be handled by the microprocessor in one operation and also, as a rule, thewidth of the main data bus. Word sizes of 16 bits and 32 bits are the most common.

Compare byte, octet.



character

n. A letter, number, punctuation mark, or other symbol or control code that is represented

to a computer by one unit-1 byte-of information. A character is not necessarily visible,

either on the screen or on paper; a space, for example, is as much a character as is the

letter a or any of the digits 0 through 9. Because computers must manage not only so-called printable characters but also the look (formatting) and transfer of electronically

stored information, a character can additionally indicate a carriage return or a paragraphmark in a word-processed document. It can be a signal to sound a beep, begin a new

page, or mark the end of a file. See also ASCII, control character, EBCDIC.

byte

n. Short for binary term. A unit of data, today almost always consisting of 8 bits. A byte

can represent a single character, such as a letter, a digit, or a punctuation mark. Because a

byte represents only a small amount of information, amounts of computer memory and

storage are usually given in kilobytes (1,024 bytes), megabytes (1,048,576 bytes), orgigabytes (1,073,741,824 bytes). Abbreviation: B. See also bit, gigabyte, kilobyte,

megabyte. Compare octet, word

Monday, January 01, 2007ComputerElectronicsVocabulary

simplex

n. Communication that takes place only from sender to receiver. Compare duplex2

(definition 1), half-duplex2

.

duplex2

n. 1. Simultaneous communications, in both directions, between the sender and receiver.

Also called duplex transmission, full-duplex transmission. See also half-duplex

transmission. 2. Photographic paper on which an image can be printed on both sides

half-duplex2

n. Two-way electronic communication that takes place in only one direction at a time.

Compare duplex2 (definition 1), simplex transmission. Also called half-duplextransmission

Simple Mail Transfer Protocol

n. A TCP/IP protocol for sending messages from one computer to another on a network.

This protocol is used on the Internet to route e-mail. Acronym: SMTP. See also

communications protocol, TCP/IP. Compare CCITT X series, Post Office Protocol.




n. A set of rules or standards designed to enable computers to connect with one another

and to exchange information with as little error as possible. The protocol generally

accepted for standardizing overall computer communications is a seven-layer set of

hardware and software guidelines known as the OSI (Open Systems Interconnection)model. A somewhat different standard, widely used before the OSI model was developed,

is IBM's SNA (Systems Network Architecture). The word protocol is often used,sometimes confusingly, in reference to a multitude of standards affecting different

aspects of communication, such as file transfer (for example, XMODEM and

ZMODEM), handshaking (for example, XON/XOFF), and network transmissions (for

example, CSMA/CD). See also ISO/OSI model, SNA.

TCP/IP

n. Acronym for Transmission Control Protocol/ Internet Protocol. A protocol suite (or set

of protocols) developed by the Department of Defense for communications overinterconnected, sometimes dissimilar, networks. It is built into the UNIX system and has

become the de facto standard for data transmission over networks, including the Internet


n. A protocol for servers on the Internet that receive, store, and transmit e-mail and for

clients on computers that connect to the servers to download and upload e-mail.

Acronym: POP.

first in, first out

n. A method of processing a queue, in which items are removed in the same order in

which they were added-the first in is the first out. Such an order is typical of a list of

documents waiting to be printed. Acronym: FIFO. See also queue. Compare last in, first

out.

last in, first out

n. A method of processing a queue in which items are removed in inverse order relative

to the order in which they were added-that is, the last in is the first out. Acronym: LIFO.

See also stack . Compare first in, first out.

stack

n. A region of reserved memory in which programs store status data such as procedureand function call addresses, passed parameters, and sometimes local variables. See also

pop, push (definition 1). Compare heap (definition 1).



queue

n. A multi-element data structure from

which (by strict definition) elements can beremoved only in the same order in which

they were inserted; that is, it follows a first

in, first out (FIFO) constraint. There are also

several types of queues in which removal is

based on factors other than order of insertion-for example, some priority value

assigned to each element. See also deque,

element (definition 1). Compare stack .

proxy

n. A computer (or the software that runs on it) that acts as a barrier between a network

and the Internet by presenting only a single network address to external sites. By actingas a go-between representing all internal computers, the proxy protects network identities

while still providing access to the Internet. See also proxy server.

proxy server

n. A firewall component that manages Internet traffic to and from a local area network

(LAN) and can provide other features, such as document caching and access control. A

proxy server can improve performance by supplying frequently requested data, such as apopular Web page, and can filter and discard requests that the owner does not consider

appropriate, such as requests for unauthorized access to proprietary files. See also

firewall.

Protocols




n. A set of rules or standards designed to enable computers to

connect with one another and to exchange information with as little

error as possible. The protocol generally accepted for standardizing

overall computer communications is a seven-layer set of hardware

and software guidelines known as the OSI (Open SystemsInterconnection) model. A somewhat different standard, widely

used before the OSI model was developed, is IBM's SNA (Systems

Network Architecture). The word protocol is often used,

sometimes confusingly, in reference to a multitude of standards

affecting different aspects of communication, such as file transfer

(for example, XMODEM and ZMODEM), handshaking (for

example, XON/XOFF), and network transmissions (for example,

CSMA/CD). See also ISO/OSI model, SNA.


n. A set of rules or standards designed to enablecomputers to connect with one another and toexchange information with as little error as

possible. The protocol generally accepted forstandardizing overall computer communicationsis a seven-layer set of hardware and softwareguidelines known as the OSI (Open SystemsInterconnection) model. A somewhat differentstandard, widely used before the OSI model wasdeveloped, is IBM's SNA (Systems Network

Architecture). The word protocol is often used,sometimes confusingly, in reference to amultitude of standards affecting differentaspects of communication, such as file transfer




6a Internet Protocol (IP ) tifwmeufy½d kwk daum 6b communications protocol

qufoG,fa&;y½d kwdkaum6c Transmission Control Protocol/Internetprotocol(TCP/IP) a'wmydk Y&mwGif

xdef;csKkyfaomy½d kwd kaum^tifwmeufy½dkwdkaum

6d Simple Mail Transfer Protocol (SMTP) ½d k;&Sif;aomar;vf x&efpzm; y½dkwd kaum

6e Post Office Protocol(POP) pmwdkufy½d kwdkaum

$$$$$$$$$$$$$

6a Internet Protocol (IP ) tifwmeufy½d kwk daum

data messages rsm;udk packets rsm;tjzpfajymif;vJzGJ.pnf;jcif;? ,if; packets rsm;ud k sender

rS destination network and station oufqd kif&mvrf;aMumif;toD;oD;od k Ywifay;jcif; (routing)?Destination a&mufaomtcg packets rsm;ud krlv data messages rsm;tjzpfjyefvnf ajymif;vJzG J Upnf;jcif; (reassembly of packets into the original data messages at the

destination) ponf hvkyfief;rsm;aqmif&Gufay;onf h TCP/IP y½d kwkdaum\tpdwftyd kif;/

6b communications protocol(n)qufoG,fa&; y½d kwd kaum

uGefysLwmwmwckESif hwckcsdwfquf&efESif howif;tcsuftvufrsm; zvS,f&mwGifvd kufem&aom pHowf rSwfcsufrsm;( standards)ESif hpnf;rsOf;rsm; ( A set of rules )/ þ y½d kwdkaumrsm;ud k vdkufemygu



trSm;teJqH k;jzif hvG,fulacsmarG UpG m qufoG,fEd kifrnf/ trsm;vufcHaomy½d kwd kaumwGif Hardware

& Software (7)vT mpkjzif h zG J Upnf;xm;ygonf/

6c Transmission Control Protocol/Internet Protocol (TCP/IP)

Data yd k Y&mwGifxdef;csKkyfaomy½dkwd kaum^tifwmeufy½d kwd kaumrsdK; rwlaomuGef,ufrsm; qufoG,f &mwGif toHk;jyKaomy½d kwdkaumtpk/ Department of Defense for communications

rSpwiftoHk;jyKonf/ tifwmeuftygt0if uGef,ufrsm;rSwqif h data yd k Y&mwGiftrsm;vufcH toHk;jyKaom standard y½d kwd kaumjzpfvmonf/

6d Simple Mail Transfer Protocol (SMTP)

½d k;&Sif;aomar;vfx&efpzm; y½dkwd kaum? þy½dkwd kaumud k tifwmeufwGiftD;ar;vfrsm;yd k U&mwGiftoH k;jyKygonf/

6e Post Office Protocol(POP)

pmwdkuf y½d kwd kaum tifwmeufay:wGiftD;ar;vfrsm;vufcHjcif;? od kavS mifodrf;qnf; xm;jcif;?yd kYjcif;jyK vkyf&mwGif servers rsm;rStoH k;jyKaom y½d kwdkaum/ servers rsm;ESif hcsdwfqufxm;aomclient computers rsm;uvnf;tD;ar;vfrsm;u upload/download vkyf&ef pop y½d kwd kaumud kyif toH k;jyKonf/



.

computervocabularytranslation23feb08 1 spam pyrf; 2 wysbygi 0wfpfbd*sd 3 firewall zkd

Documents