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: disk, CD, DVD, Flash drives Storage Device: mechanical; disk drives, CD drives, USB drives Storage = Medium + Device

Storage Process Data copied from storage device to RAM Data Processed in RAM –temporary high speed storage Data copied back to storage medium (permanent) – SAVE –Storing data is writing/saving file –Retrieving data is reading/loading/opening file

Storage Comparison Magnetic Optical FLASH MEMORY Optical

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 VersatilityDurabilitySpeed –Access time –Milliseconds –Random vs. sequential access –Data transfer rate Capacity –KB, MB, GB, TB –Disk density Hard drive

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

Adding Storage Devices Upgrading System Unit contains drive bays

“Ancient History” Lesson 3½” disk: 1.44 MB Zip disks (Iomega): 100 and 250 MB SuperDisks (Imation): 120 MB

Hard Disks (Fixed Disks)‏ Hard drives Storage Capacity varies. Very fast access times (rpm)‏ Platters divided into tracks, sectors, cylinder Controller (circuit board)‏ –Ultra AT –EIDE –SCSI Head Crash is failure.

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 (saving a back-up)‏

DVD Technology Digital Video Disk Originally alternative to VHS tapes and VCRs 4.7 GB Manufactured DVD players 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

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 –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 sizes vary (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)‏ MaterialsCost Qualityvs.Price Speed (ppm or cps)‏

Common Printer Types Ink Jet printer Laser printer

Ink Jet Printer Nozzle-like print head sprays ink Low cost Can smudge Color; black and white

Laser Printer Same technology as photocopier Fax High quality Fast

Keyboards

Peripherals 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

Issue Recycling Computers