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Computer Hardware

Technologies that enable a computer to store and retrieve data and programs



Introduce Storage Technology

Compare Storage Technologies

Compare Storage Media and Devices

Explore Floppy Disk Technology

Explore CD/DVD Technology

Understand Expansion Slots, Cards, Ports, and Cables

Compare Display Devices

Compare Printers

Examine Keyboards

Explore Peripheral Devices



Storage Medium: (the item)




Paper, etc

Storage Device: ( the mechanical)

disk drives,

Floppy drives

CD drives

Hard drives

Data Storage Process

Data is copied into RAM because the computer will operating faster by retrieving the data from this location rather than from any other storage location.

RAM data is temporary, it is replaced with the new data that you are working on.

Magnetic Storage

Magnetizes particles on the surface

Permanent, but modifiable

Hard disk, floppy disk, zip disk and tape

Read-write head

Not very durable, can be destroyed by magnets

Optical Storage

Stores data as light and dark spots on the disk surface.

Called, Pits and lands


Comparing Storage Devices




Speed is the Access time and the data transfer rate

Capacity is measured in

Kilobytes kB,

Megabytes MB,

Gigabytes GB,

Terabytes TB

Comparing Storage Devices

Adding Storage Devices

Upgrading your computer

Your computer contains unused drive bays

Floppy Disks are Portable

Hard Disks (Fixed Disks)

One or more platters with read/write heads

Capacity averages 40 GB

Very fast access times (rpm)

Platters divided into tracks, sectors, cylinder

Controller (circuit board)

Ultra AT



Head Crash


Redundant Array of Independent Disks

Redundant Array of Inexpensive Disks

Combines two or more drives

Faster access and protects data from loss

Mainframes and servers

CD Technology

CD-ROM: Compact Disk Read-Only Memory

Manufactured; cannot change; 680 MB

CD-R: Compact Disk Recordable

You record; cannot be erased or modified

CD-RW: Compact Disk Rewritable

You record; can erase and rewrite

DVD Technology

Digital Video Disk

Originally alternative to VCR

4.7 GB

Can play CD-ROM and most CD-Rs and CD-RWs

Manufacture permanently stamped the DVD so you can not change it.


Data Bus: circuits on which data travels within the computer

Between RAM and CPU

Between RAM and storage devices

Expansion Bus

Part of data bus between RAM and the peripherals

Expansion Slots and Cards

Cards also called expansion boards, controller cards, adapters

Desktops have 4 to 8 slots

Standard cards

Graphics or video card

Modem card

Sound card

Network card

Expansion Slot Types

ISA: Industry Standard Architecture

Older; modems and slow devices

PCI: Peripheral Component Interconnect

Fast; graphics, sound, video

AGP: Accelerated Graphics Port

Fast; graphics


Personal Computer Memory Card International Association

Found on notebook computers

Type I, II, III

Expansion Ports

Jacks or connectors

Mouse, keyboard, serial, USB


Display Devices

Graphics card

Video memory

AGP expansion card

Accelerator technology

CRT: Cathode Ray Tube

Inexpensive and dependable

LCD: Liquid Crystal Display

Expensive; found on notebooks

Limited viewing angles

Active Matrix or TFT (thin film transistor)

Display Device Image Quality

Screen size (13 to 21)

Dot pitch

Distance between like-colored pixels

.26 or .23 typical (smaller is better)


Horizontal and vertical pixels on screen

640 x 480, 800 x 600 and 1024 x 768

Color or Bit Depth

Number of colors that can be displayed

24-bit (true color) = millions of colors

Printer Comparison Criteria

Printer Types

Ink Jet printer

Solid Ink printer

Thermal Transfer printer

Dye Sublimation printer

Laser printer

Dot Matrix printer

Ink Jet Printer

Nozzle-like print head sprays ink

Low cost

Can smudge

Color; black and white

Solid Ink Printer

Crayon-like ink is melted and sprayed

Vibrant colors on most types of paper

Thermal Transfer Printer

Uses wax that is melted

Needs special paper/transparencies


Dye Sublimation Printer

Like wax transfer, but uses heated dye

Need special paper

Excellent color quality


Laser Printer

Same technology as photocopier


High quality




Device driver software on CD

Plug and Play (PnP)

TechTalk: Windows Registry

Registry is the glue that binds together the PC hardware, peripherals, application and system software

Operating system needs to know (and registry holds)

where peripherals are located

what has been installed

how they are configured

how you want to use them

Techtalk: continued

Examples: resolution, shortcuts, system events, network settings, uninstall routines

System.dat and User.dat

Registry updated when you install or remove hardware or software


Computer Hardware