INFO 130.20INFO 130.20

Martin van BommelMartin van Bommel

1999-20001999-2000

What is a Computer?What is a Computer?

ComputerComputer - electronic device that accepts - electronic device that accepts input, performs calculations, and produces the input, performs calculations, and produces the required resultsrequired results

HardwareHardware - components of computer system - components of computer system that you can see and touch that you can see and touch

e.g. keyboard, screen, disk drive, printer, circuit e.g. keyboard, screen, disk drive, printer, circuit boardboard

SoftwareSoftware - list of instructions for computer to - list of instructions for computer to perform a specific taskperform a specific task

e.g. operating system, word processor, e.g. operating system, word processor, WindowsWindows

Input - Processing - OutputInput - Processing - Output

Input Input - what you type, read, or enter into - what you type, read, or enter into computercomputer– Devices -Devices - keyboard, mouse, scanner, sensors keyboard, mouse, scanner, sensors

Processing Processing - changing the input data via - changing the input data via formatting, sorting, and calculationsformatting, sorting, and calculations– DevicesDevices - components on motherboard, CPU, ALU, - components on motherboard, CPU, ALU,

memorymemory OutputOutput - results of computer processing - results of computer processing

– DevicesDevices - screen, printer, plotter, signals - screen, printer, plotter, signals StorageStorage - save information for later processing - save information for later processing

– Devices - memory, diskette, hard disk, tapeDevices - memory, diskette, hard disk, tape

Types of ComputersTypes of Computers

MicrocomputersMicrocomputers or Personal Computers (PCs)or Personal Computers (PCs)– inexpensive - $500 - $15,000inexpensive - $500 - $15,000– small enough to fit on desksmall enough to fit on desk– CPU contained on single chipCPU contained on single chip

Minicomputers and MainframesMinicomputers and Mainframes– $15,000 - millions$15,000 - millions– too large for desktoptoo large for desktop– larger capacity for storing and manipulating datalarger capacity for storing and manipulating data

ServersServers– Usually fast microcomputers or small minicomputersUsually fast microcomputers or small minicomputers– Lots of memory and disk spaceLots of memory and disk space

Processing HardwareProcessing Hardware

Microprocessor or Central Processing Unit Microprocessor or Central Processing Unit (CPU)(CPU)– integrated circuit chip on the motherboardintegrated circuit chip on the motherboard– performs arithmetic and logical operationsperforms arithmetic and logical operations

Input/Output Interface Cards (I/O Cards)Input/Output Interface Cards (I/O Cards)– provide connection between CPU and I/O devicesprovide connection between CPU and I/O devices

Floppy and Hard Disk DrivesFloppy and Hard Disk Drives– storage external to the motherboardstorage external to the motherboard

MemoryMemory– temporary storage on the motherboardtemporary storage on the motherboard

Data RepresentationData Representation

bit - binary digit - 0 or 1bit - binary digit - 0 or 1 byte - eight bitsbyte - eight bits ASCII code - each character represented by 8 ASCII code - each character represented by 8

bitsbits

NumberNumber Binary Binary CharacterCharacter ASCII . ASCII .

0 000000000 00000000 A A 01000001 01000001

1 000000011 00000001 B B 0100001001000010

...... ... ...

255 11111111255 11111111 Z Z 01011010 01011010

MemoryMemory

ROM - Read-Only MemoryROM - Read-Only Memory– permanent memory installed by manufacturerpermanent memory installed by manufacturer– initial instructions for computer on start-upinitial instructions for computer on start-up

RAM - Random-Access MemoryRAM - Random-Access Memory– temporary storage for data and instructionstemporary storage for data and instructions– lost when power offlost when power off

Byte = 8 bitsByte = 8 bits K - Kilobyte - 1024 bytesK - Kilobyte - 1024 bytes MB - Megabyte -1024 x 1024 bytes = 1,048,576 MB - Megabyte -1024 x 1024 bytes = 1,048,576

bytesbytes GB - Gigabyte - 1024 x MB = 1,073,741,824 bytesGB - Gigabyte - 1024 x MB = 1,073,741,824 bytes

Output DevicesOutput Devices

Monitor - displays output in pixels - picture Monitor - displays output in pixels - picture elementselements– cathode ray tube (CRT)cathode ray tube (CRT)– liquid crystal display (LCD)liquid crystal display (LCD)– resolution measured in pixelsresolution measured in pixels

CGA - 320 x 200CGA - 320 x 200 VGA - 640 x 480VGA - 640 x 480 SVGA - 1024 x 768SVGA - 1024 x 768

Graphics Adapter - Display Card - Display AdapterGraphics Adapter - Display Card - Display Adapter– connects monitor to motherboardconnects monitor to motherboard– monitor must support its resolutionmonitor must support its resolution– contains memory to store image for faster processingcontains memory to store image for faster processing

PrintersPrinters

Output from printer called “hard copy”Output from printer called “hard copy” Speed measured in ppm - pages per minute - 4, Speed measured in ppm - pages per minute - 4,

6, 8, 126, 8, 12 Three types:Three types:

– dot-matrix : pins striking ribbon make dots on paperdot-matrix : pins striking ribbon make dots on paper 9-pin or 24-pin vertically9-pin or 24-pin vertically

– Ink-jet : tiny dots of ink sprayed on paperInk-jet : tiny dots of ink sprayed on paper black or colorblack or color color should have separate black cartridge to save expensive color should have separate black cartridge to save expensive

colorcolor

– Laser jet : laser bonds black powder (toner) to paperLaser jet : laser bonds black powder (toner) to paper quality in dots per inch (dpi) 300 dpi standard, 600 dpi betterquality in dots per inch (dpi) 300 dpi standard, 600 dpi better

Storage DevicesStorage Devices

Diskettes - most common 3 1/2” HD - 1.44 MBDiskettes - most common 3 1/2” HD - 1.44 MB– write protection - window on disk to prevent writingwrite protection - window on disk to prevent writing

Hard Disks - common 540 MB to 4.2 GBHard Disks - common 540 MB to 4.2 GB CDs - 680 MB or more CDs - 680 MB or more

– transfer at 150 K per secondtransfer at 150 K per second– double-speed - 300 K per second - sound and videodouble-speed - 300 K per second - sound and video– quad-speed - 600 K per second - true multimediaquad-speed - 600 K per second - true multimedia

Tape - usually for backupTape - usually for backup– slow, sequential accessslow, sequential access

Communications HardwareCommunications Hardware

Modem or Fax modemModem or Fax modem– transmit digital data over analog phone linestransmit digital data over analog phone lines– speed measured in bits per secondspeed measured in bits per second– 9600 bps; 14,400 bps; 28,800 bps; 33,600 bps; 52 9600 bps; 14,400 bps; 28,800 bps; 33,600 bps; 52

KbpsKbps– fax capabilities allow sending and receiving of faxesfax capabilities allow sending and receiving of faxes

Network Interface CardNetwork Interface Card– interface between computer and networkinterface between computer and network– must worry about network protocols and cable typesmust worry about network protocols and cable types– typically ethernet card with coaxial or twisted-pair typically ethernet card with coaxial or twisted-pair

connectorsconnectors

Computer SoftwareComputer Software

instructions for computer to accomplish a taskinstructions for computer to accomplish a task

1. Systems software - run fundamental 1. Systems software - run fundamental operationsoperations– loading programs and data into memoryloading programs and data into memory– executing programsexecuting programs– saving data on disksaving data on disk– performing I/Operforming I/O

2. Applications software - applies computer to 2. Applications software - applies computer to goalsgoals– word processing, spreadsheet, database, graphicsword processing, spreadsheet, database, graphics

Systems SoftwareSystems Software

Operating System - provides system controlOperating System - provides system control– DOS - Disk Operating System MS-DOS or PC-DOS - Disk Operating System MS-DOS or PC-

DOSDOS– control computer via a series of commandscontrol computer via a series of commands

Operating environments - between OS and Operating environments - between OS and useruser– graphical interface for DOS commandsgraphical interface for DOS commands– Windows 2.0, 3.0, and 3.1 - run above DOSWindows 2.0, 3.0, and 3.1 - run above DOS– Windows ‘95 and Windows NT - run without DOSWindows ‘95 and Windows NT - run without DOS– many programs now require a Windows many programs now require a Windows

environment to runenvironment to run

Applications SoftwareApplications Software

Word processing softwareWord processing software– electronically create, edit, format, and print documentselectronically create, edit, format, and print documents– move paragraphs, check spelling, create tables and move paragraphs, check spelling, create tables and

columnscolumns– modify margins, correct typos, preview printingmodify margins, correct typos, preview printing– Microsoft Word, WordPerfectMicrosoft Word, WordPerfect

Electronic SpreadsheetElectronic Spreadsheet– perform calculations with numbers in rows and columnsperform calculations with numbers in rows and columns– type data, enter formulas, calculate results, create type data, enter formulas, calculate results, create

graphsgraphs– Microsoft Excel, Borland’s Quattro Pro, Lotus 1-2-3Microsoft Excel, Borland’s Quattro Pro, Lotus 1-2-3

Applications Software IIApplications Software II

Database software - manage and manipulate info.Database software - manage and manipulate info.– search, sort, select, delete, and update a databasesearch, sort, select, delete, and update a database– create reports, answer questions, create entry formscreate reports, answer questions, create entry forms– Microsoft Access, Borland’s ParadoxMicrosoft Access, Borland’s Paradox

Graphics software - create illustrations, diagrams, Graphics software - create illustrations, diagrams, graphs and chartsgraphs and charts– draw lines, boxes, circles, fill and erase, enlarge, printdraw lines, boxes, circles, fill and erase, enlarge, print– include include clipartclipart - predrawn images - predrawn images– Microsoft Paintbrush, CorelDRAW, Harvard GraphicsMicrosoft Paintbrush, CorelDRAW, Harvard Graphics