Computer Hardware Unit B

Objectives Introduce Storage Technology Compare Storage Technologies Compare Storage Media and Devices Explore Floppy Disk Technology Explore CD/DVD Technology

Objectives Understand Expansion Slots, Cards, Ports, and Cables Compare Display Devices Compare Printers Examine Keyboards Explore Peripheral Devices

Storage Technology Storage = Medium + Device Storage Medium: disk, CD, DVD Storage Device: mechanical; disk drives, CD drives Lab: working with binary numbers Storage = Medium + Device

Storage Process 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

Storage Comparison Magnetic Optical vs.

Magnetic Storage Magnetizes microscopic particles on medium surface Permanent, but modifiable Hard disk, floppy disk, zip disk and tape Read-write head Not very durable

Optical Storage Stores data as microscopic light and dark spots on disk surface Pits and lands Uses laser lights More durable

Comparing Storage Devices Versatility Durability Speed Access time Milliseconds Random vs. sequential access Data transfer rate Capacity KB, MB, GB, TB Disk density

Comparing Storage Devices Device Cost Media Cost Capacity Floppy disk $40-99 $.30 1.44 MB Zip disk $139 (avg) $11.00 250 MB Fixed disk $150 (avg) - NA - 40 GB (avg) CD-R $130-200 $.50 680 MB CD-RW $1.50 Writable DVD $500 (avg) $25.00 5.2 GB Tape $199 (avg) $50.00 30 GB (avg)

Adding Storage Devices Upgrading System Unit contains drive bays CD video: drive bays

Floppy Disks are Portable Zip disks (Iomega): 100 and 250 MB SuperDisks (Imation): 120 MB 3½” disk: 1.44 MB Info web: floppy disk drives

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 EIDE SCSI Head Crash CD video: how a hard disk works

RAID Redundant Array of Independent 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 modify Archiving Data Info web: CD and DVD

DVD Technology Digital Video Disk Originally alternative to VCR 4.7 GB Manufactured Can play CD-ROM and most CD-Rs and CD-RWs

Busses 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 CD video: inserting an expansion 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

PCMCIA (PC Card) Personal Computer Memory Card International Association Found on notebook computers Type I, II, III

Expansion Ports Jacks or connectors Mouse, keyboard, serial, USB Cables

Display Devices Graphics card CRT: Cathode Ray Tube 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) Info web: display devices

Display Device Image Quality Screen size (13” to 21”) Dot pitch Distance between like-colored pixels .26 or .23 typical (smaller is better) Resolution 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 Resolution (dpi) Quality vs. Price Materials Cost Info web: printer buying guide Speed (ppm or cps)

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 Expensive

Dye Sublimation Printer Like wax transfer, but uses heated dye Need special paper Excellent color quality Expensive

Laser Printer Same technology as photocopier Fax High quality Fast CD video: laser printer

Keyboards Lab: operating a personal computer

Peripherals Device driver software on CD Plug and Play (PnP) CD screentour: peripheral devices examples

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

Issue CD: exercise Why Recycle Computers?

Computer Hardware End