designed to process instructions alu arithmetic logic unit cu control unit
TRANSCRIPT
Designed to process instructions
ALU arithmetic logic unit
CU control unit
RAM Random Access Memory
ROM Read Only Memory
Temporary (volatile) holding area for data, application software and operating system
Less storage than disk Capacity measured in MB (128 - 256
MB) Speed in nanoseconds
Random Access MemoryRandom Access Memory
Permanent on a chip from manufacturer
Holds computer start up routine, which are hard-wired instructions
Read-Only MemoryRead-Only Memory
The form in which information is conceived, manipulated and recorded on a digital device.
Uses discrete digits/electronic signals- 1,0 (bits - binary digits)- On/Off - Yes/No
Byte = 8 bits = 1 character
Depends on computer ASCII (7 bits) Extended ASCII (8 bits -
current PCs) EBCDIC (8 bits - older IBM
machines ) Unicode (16 bits - good for
languages - future)
Bit = b Nibble = Half of a byte Byte = B Kilobyte (KB) (1024 bytes) Megabyte (MB) (Million bytes) Gigabyte (GB) (Billion bytes) Terabyte (TB) (Trillion bytes)
Dial-up connection via modem (56K) Cable modems
Network card and cable modem required Always-on and 25 times faster than dial-up
ISDN (Integrated Services Digital Network) 64K or 128K Always-on and expensive
DSL (Digital Subscriber Line) and xDSL Up to 125 times faster than dialup
DSS (Digital Satellite Service) 500K
Need proximity to a telephone switching stationNeed proximity to a telephone switching station
Account = Mailbox Message Attachment ASCII vs HTML format Netiquette
userid@computer
E-mail servers Store-and-forward technology Types
POP (Post Office Protocol) used via ISP IMAP (Internet Messaging Access
Protocol) Web-based like Hotmail
System SoftwareSystem Software
Application SoftwareApplication Software
Operating Operating SystemsSystems
Device Device DriversDrivers UtilitiesUtilities ProgrammingProgramming
LanguagesLanguages
DOSDOS
WindowsWindows
LinuxLinux
UNIXUNIX
Mac OSMac OS
DocumentDocumentProductionProduction
SpreadsheetSpreadsheetSoftwareSoftware
AccountingAccounting& Finance& Finance
MathematicalMathematicalModelingModeling
StatisticalStatistical
EntertainmentEntertainment
DataDataManagementManagement
GraphicsGraphics
MusicMusic
VideoVideo EducationalEducational
ReferenceReference
Computer program main executable program (.exe)
Support module called by the program (.dll)
Data module Example: a dictionary file or a file that is not
supplied by the user
Computer languages Source code High-level languages: COBOL, C++, Java
Machine language Compiler
Creates object code in single batch Interpreter
Converts one instruction at a time Common with web-based scripts (part of web
page)
Interacts with application software, device drivers & hardware to manage computers resources
Multitasking CTRL-ALT-DEL GUI
graphical user interface Utilities
Software License: a legal contract that defines the ways in which you may use a computer program.
Copyright: a form of legal protection that grants the author of an original work an exclusive right to copy, distribute, sell and modify that work.
Software piracy For contract to take effect:
Open a shrink-wrap license product Agree to an installation agreement
Shareware: try before you buy on the honor system
Freeware: no fee - can use, but not alter or sell
Open Source: uncompiled source code that can be changed - sold or free
Public Domain: can be copied, altered and resold
Power up ROM runs bootstrap program POST (Power-on self-test)
Identifies and checks peripherals ROM loads operating system from
hard disk into RAM Checks configuration and
customization startup routines Safe Mode if this process is not
successful
A collection of data on a storage medium
Filename conventions Filename extension
.txt.txt.txt.txt .jpg.jpg.jpg.jpg .exe.exe.exe.exe .doc.doc.doc.doc
Device drive letters A: C: D: Directory
Root Directory (C:\) Subdirectory or folder (C:\Documents) File specification or Path File size and date
Filename extensionFilename
Secondary folder
Primary folder
Drive letter
C:\Music\Reggae\Marley One Love.mp3 C:\Music\Reggae\Marley One Love.mp3
Move to Recycle Bin in Windows Undelete Empty Bin
Helps you organize your computer files
File/Save and File/Open Utilities like Windows Explorer or
MAC Finder list, find, move, copy, delete, rename
Save vs. Save As
Filing cabinet model Metaphor to help you
visualize files on a storage device
Windows Explorer Folder hierarchy
Storage medium formatted into tracks /sectors electronically
File system keeps track of names and file locations.
FAT (File Allocation Table) on each disk keeps track of where all files are. If damaged, you lose everything.
Storage Medium: disk, tape, CD, DVD holds data
Storage Device: disk drives, CD drives mechanical device
Storage = Medium + Device
Data copied from storage device to RAM
Processed in RAM volatile (temporary) high speed
storage Data copied back to storage medium
(permanent) Storing data is writing/saving file Retrieving data is
reading/loading/opening file
Magnetizes microscopic particles on medium surface
Permanent, but modifiable Hard disk, floppy disk, zip disk and tape Read-write head Not very durable
Stores data as microscopic light and dark spots on disk surface
Pits and lands Uses laser lights More durable
Versatility versatile devices can access data from
several different media; i.e., DVD drive – data DVDs, DVD movies, audio CDs, etc.
Durability mishandling, environmental factors
Speed access time milliseconds (ms – thousandths of a
second) random versus sequential access
Most common 3 ½” 1.44 MB (1,440,000 bytes)
Write protect window Others
zip disks (100 MB and 250 MB) SuperDisks (120 MB)
Compatibility
CD-ROM: Compact Disk Read-Only Memory manufactured; cannot change; up to 680MB;
more durable CD-R: Compact Disk Recordable
you record; cannot be erased or modified CD-RW: Compact Disk Rewritable
you record; can erase and modify
Digital Video Disk originally an alternative to VCR Manufactured Can play CD-ROM and most CD-Rs and CD-
RWs
USB flash drive CompactFlash (CF) cards
high-end digital cameras MultiMedia cards (MMC)
Smaller; mobile phones, pagers, cameras SecureDigital (SD) cards
MP3 storage
Screen size (13” to 21”) measured
diagonally viewable image
size (vis) Dot pitch
measure of image clarity
smaller is better
Resolution horizontal and vertical pixels displayed on the screen
640 x 480, 800 x 600, 1024 x 768 (higher is better)
Color depth (or bit depth) number of colors that
can be displayed 24-bit (true color) =
millions of colors
Resolution (dpi) Materials cost Speed (ppm or cps) Quality versus Price
device driver Plug and Play (PnP)