designed to process instructions alu arithmetic logic unit cu control unit

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)