cse120wi11lec06[1] encoding bits bytes letters

8/6/2019 Cse120wi11lec06[1] Encoding Bits Bytes Letters

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2/19

Howsitgoing? AfterImageSurveytodayby5:00 Thethreadsofthisclass

1/14/11 2010 Larry Snyder, CSE 2

0s and 1s Glories

lab3: binary & hex -- numbers

today lecture -- letters

Lightbot 2.0

functional abstraction

lab 1: symbolic lightbotlab 2: functions with lightbot

Processing

lab 4: practice w/Processing

Social Network

FactsAbilities Computing World


3/19

WehavewrittentwokindsofProcessingprograms

static,whichonlydrawapicture

dynamic,whichkeepdrawingapicture


click

Whats The Difference?


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1/14/11 (c) 2010 Larry Snyder, CSE 2010 Larry Snyder, CSE

TheDivingBellandtheButterflyJeanDominiqueBauby


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AprotocolforYes/Noquestions Oneblink==Yes Twoblinks==No

PandAimpliesthatthisisnotthefewestnumberofblinksreally?


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InEnglishETAOINSHRDLU


7/19


Howmanyquestionstoencode: Plusachange,plusc'estlammechose?

AskinginFrequencyOrder:ESARINTULOMDPCFBVHGJQZYXKW

129


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AskinginFrequencyOrder:ESARINTULOMDPCFBVHGJQZYXKW

AskinginAlphabeticalOrder:ABCDEFGHIJKLMNOPQRSTUVWXYZ

1612


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AskinginFrequencyOrder:247ESARINTULOMDPCFBVHGJQZYXKW

AskinginAlphabeticalOrder:324ABCDEFGHIJKLMNOPQRSTUVWXYZ


10/19

Spellingbygoingthroughthelettersisanalgorithm

Goingthroughthelettersinfrequencyorderisaprogram(also,analgorithmbutwiththeorderspecifiedtoaparticularcase,i.e.FR)

Thenursesdidntlookthisupinabooktheyinventedittomaketheirworkeasier;

theywerethinkingcomputationally,thoughtheyprobablydidntknowit



11/19


PandAisabinaryrepresentationbecauseituses2patterns

Bititsacontractionforbinarydigit

apositioninspace/timecapableofbeingsetanddetectedin2patterns

Sherlock Holmess Mystery of Silver Blaze --a popular example where absent gives

information the dog didnt bark, that isthe phenomenon wasnt detected


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Abyteiseightbitstreatedasaunit AdoptedbyIBMin1960s Astandardmeasureeversince BytesencodetheLatinalphabetusingASCIIthe

AmericanStandardCodeforInformation

Interchange

01010101

01010111


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01000011

01010011

01010000

0100 1000|0111 0101|0111 0011|0110 1011|0110 1001|0110 0101|0111 0011|0010 0001


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UniformTransformation

Formatforbytes

(UTF8)isuniversalallcharactershaveaplace:1,2,3,4B


15/19


UniformTransformation

Formatforbytes

(UTF8)isuniversalallcharactershaveaplace:1,2,3,4B

spnou


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Bitsandbytesencodetheinformation,butthatsnotall

Tagsencodeformatandsomestructureinwordprocessors

TagsencodeformatandsomestructureinHTML IntheOxfordEnglishDictionarytagsencode

structureandsomeformatting

Tagsareoneformofmetadata:metadataisinformationaboutinformation


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byte (baIt). Computers. [Arbitrary, prob. influenced by bit sb.4 and bite sb.] A group of eight

consecutive bits operated on as a unit in a computer. 1964Blaauw& Brooks in IBM Systems

Jrnl. III. 122 An 8-bit unit of information is fundamental to most of the formats [of the System/360]. A consecutive group ofn such units constitutes a field of length n. Fixed-length fields of

length one, two, four, and eight are termed bytes, halfwords, words, and double words

respectively. 1964IBM Jrnl. Res. & Developm. VIII. 97/1 When a byte of data appears from an

I/O device, the CPU is seized, dumped, used and restored. 1967P. A. StarkDigital Computer

Programmingxix. 351 The normal operations in fixed point are done on four bytes at a time.1968Dataweek24 Jan. 1/1 Tape reading and writing is at from 34,160 to 192,000 bytes per

second.

byte baIt. Computers.Arbitrary, prob. influenced by bit n.4andbite n. A group of eight consecutive bitsoperated on as a unit in a computer. 1964Blaauw &amp.Brooks in IBM Systems Jrnl. III. 122 An 8-bit unit of information is fundamental to most of the formats of the System/

360.&es.A consecutive group of n such units constitutes a field oflength n.&es.Fixed-length fields of length one, two, four, and eight aretermed bytes, halfwords, words, and double words respectively. 1964 IBM Jrnl. Res. &amp. Developm. VIII. 97/1When a byte of data appears from an I/O device, the CPU is seized, dumped,used and restored. 1967 P. A. Stark DigitalComputer Programming xix. 351 The normal operations in fixedpoint are done on four bytes at a time.1968 Dataweek24 Jan. 1/1 Tape reading and writing is at from 34,160 to 192,000bytes per second.


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Thisweekwehaveseen Bitsencodenumbersusingthebinary

representation1111100111

BitsencodelettersusingASCIIforNorthAmericanandWesternEuropeanlanguages

Thissuggestsanprinciplewewillsoonargue: Allinformationcanberepresentedwithbits



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Computersjoinphysical&logicaldomainssophysicaldevicesdoourlogicalwork

Symbolsrepresentthings1to1:0,1 Createsymbolsbygroupingpatterns:01010111 PandArepresentationisfundamental:present? Bit,aplacewhere2patternsset/detect

ASCIIisabyteencodingofLatin

bet Inadditiontocontent,encodestructure:meta

cse120wi11lec06[1] encoding bits bytes letters

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