Introduction To ComputersIntroduction To Computers

What is a computer?What is a computer?

What Is A Computer? What Is A Computer?

A programmable machine

– Responds to a specific set of instructions in a well-defined manner.

– Can execute a prerecorded list of instructions (a program)

CLR DATA DEF FN DIM END FOR...TO...STEP GET GOSUB GOTO IF..THEN INPUT LET NEXT ON PRINT READ REM STOP WAIT

10 PI = 0: C = 1 20 PI = PI + 4/C + 4/(C + 2) 30 PRINT PI 40 C=C+4: GOTO 20

What Is A Computer? TextbookWhat Is A Computer? Textbook

An electronic device that– Accepts data (raw facts)– Processes that data

– Produces meaningful information» Through math / logic

» Without human intervention

DATA INFORMATION

Which Computer is Best?Which Computer is Best?

A. Dell

B. Gateway

C. HP/Compaq

D. IBM

VOTE!

Which Computer is Best?Which Computer is Best?Apple (298) 9.2

Alienware (58) 8.8

Self-built (1,408) 8.4

Sony (445) 8.2

Clone (710) 8.2

Shuttle (63) 8.0

Dell (5,752) 7.9

MPC/Micron (82) 7.8

Gateway (688) 7.7

Systemax (92) 7.7

eMachines (367) 7.4

HP/Compaq (2179) 7.4

Lenovo/IBM (334) 7.4

Need A Computer?Need A Computer?

Find the cheapest Dell computer

Build it yourself

Apple (298)$500 (mini) +

monitor

Alienware (58) $659

Self-built (1,408) -

Sony (445) $700 + mon

Clone (710) -

Shuttle (63) TINY! $600 + mon

Dell (5,752) $300

Which Computer Is Best?Which Computer Is Best? 2002 PC Magazine Reader Survey

Which Computer Is Best?Which Computer Is Best? 2003 PC Magazine Reader Survey

2004 PC Mag Reader Survey2004 PC Mag Reader Survey

2005 PC Mag Reader Survey2005 PC Mag Reader Survey

2008

What Do Computers Do?What Do Computers Do?

Computers perform 4 general operations:• Input

• Processing (math / logical)

• Output

• Storage

A. keyboard and mouseB. microphone and scannerC. printer and monitorD. digital camera & PC video camera

VOTE!

All of the following are widely used input devices

except __

All of the following are widely used input devices

except __

Input DevicesInput Devices

Keyboards

Mouse

Others?

Other Input DevicesOther Input Devices

System UnitSystem Unit

System Unit System Unit

ASUS A7N266ASUS A7N266

Processor:– AMD Athlon XP1900+ OEM

RAM:– 256MB PC2700 DDR

Video:– ATI Radeon 9100 64MB Retail

Sound, Network – On board

Communications:– US Robotics 56K V90 PCI

CD-RW:– Lite-On LTR-52246S

Monitor:– Samsung 700NF

Hard Drive:– Seagate Barracuda ATA V 60GB

TOTAL: $650

Processor UnitProcessor Unit

Consists of two parts:– Central processing unit (CPU)

– Main computer memory (ram)

MemoryMemory

Main computer memory Random access memory

– RAM

Measured in bytes (chars)– KiloBytes 1000– MegaBytes 1 million– GigaBytes 1 billion

22

Bit PermutationsBit Permutations1 bit

01

2 bits

00011011

3 bits

000001010011100101110111

4 bits

00000001001000110100010101100111

10001001101010111100110111101111

Each additional bit doubles the number of possible permutations

A. display devices (screen/monitor)B. speakers and headsetsC. printersD. ports

VOTE!

All of the following are widely used output devices

except __

All of the following are widely used output devices

except __

Output DevicesOutput Devices

Printers Impact

»Daisy wheel

»Dot matrix Non-impact

»Laser

»Ink jet

Laser PrinterLaser Printer

Output DevicesOutput Devices

Display Devices (monitors or Display Devices (monitors or screens)screens)

MonitorsMonitors

CRT vs. LCD MONOCHROME

vs. Color Pixels

– 640 x 480 VGA

– 800 x 600 super VGA

– 1024 x 768 “ “

– 1280 x 1024 “ “

PixelPixel

Auxiliary StorageAuxiliary Storage

Storage of data and programs when not stored in main memory

Storage devicesStorage devices –1. Floppy disks1. Floppy disks

–2. Zip disks2. Zip disks

3. Hard disks3. Hard disks

A.A. Magnetic disksMagnetic disks

Diskettes

– 5 1/4”

– 3 1/2”

– Double sided, SS

– Double or high density

Hard Drives (Fixed Drives)Hard Drives

(Fixed Drives) Capacity measured in

megabytes or terabytes

Size to 5TB

Disk, Track, SectorDisk, Track, Sector

Track.– A ring on a disk where

data can be written.

Sector.– The smallest unit that

can be accessed on a disk.

Storage devicesStorage devices

B.B. Optical DisksOptical Disks–2. DVDs2. DVDs

–1. CD s1. CD s

CD-ROMCD-ROM

Compact disk-read only memory

600 meg 22K tracks Software distributed on CD Multimedia software CD-recorders available

– Read and write to them

Storage devicesStorage devices

C.C. TapeTape D.D. Miniature Storage MediaMiniature Storage Media

Computer SoftwareComputer Software

-System software

– Operating system

– Diagnostic Application software

– Word processing

– Spreadsheets

– Database management

– Business payroll, etc.

– Games, et. Al.

Windows VersionWindows Version Graphical user interface (GUI).

– Uses graphics and text to communicate with user.(Contrast with

DOS prompt).

Windows 3.1, 3.11.– A GUI.– Not an operating system.– DOS is still required.

Windows 98, XP– An operating system.– Includes a GUI.

CommunicationsCommunications

Transmission of data over communications channel such as telephone lines

Communications EquipmentCommunications Equipment

Computers process data using digital signals. Telephone equipment uses an analog signal. Modem.

– Converts the digital signals of a computer to an analog signal and vice versa.

– Data can be transferred from one computer to another using the telephone lines.

Internet Service ProviderInternet Service Provider

ISP – provide subscribers with software necessary for

communications » Dixie-Net

» CrossRoads

» Network One

The InternetThe Internet

The network of worldwide computers. World wide web (WWW).

– Allows users to use text, graphics, video and sound from other web sites on the internet.

Browsers.– Allow users to browse volumes of information

from computers around the world.– Netscape navigator, internet explorer.

NetworksNetworks

LAN

– Local Area Network

Computers in Same Buildings or Close Buildings Connected Through Cables.

WANWAN

WAN (Wide Area Network)– Computers Connected

Thorough Communications Channels Such As Telephone Wires, Microwaves, Etc.

Considerations for Purchasing a ComputerConsiderations for Purchasing a Computer

Determine what it will be used for. Choose your software first. Beware of hidden costs. Compare purchases alternatives. Consider the advantages of buying locally

and from direct mail order companies.

Purchasing ContinuedPurchasing Continued

Look for free software. Purchase a system compatible with the one

you use elsewhere. Consider an on-site service agreement. Use a credit card for purchasing your

system. Plan to use the system for at least 3 years.

Installing a Computer SystemInstalling a Computer System

Allow for adequate work space. Install computer in a well-designed work area. Provide adequate lighting. Install or move a phone near the computer. Save all paperwork that comes with your system. Record the serial numbers of all equipment and

software. Keep all shipping containers. Install in area where temperature and humidity can

be maintained.

Computer VirusesComputer Viruses

A computer program designed to infect computer systems by copying itself into other computer files.

The virus program spreads when infected files are executed on host and perhaps copied to another system.

Installing an anti-virus program on your computer.

An anti-virus program activates when the computer is turned on.

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