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 Storage Device: mechanical; disk drives, CD drives 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 vs. 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 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 $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 $130 -200 $1. 50 680 MB Writable DVD $500 (avg) $25. 00 5. 2 GB Tape $199 (avg) $50. 00 30 GB (avg) Floppy disk
Adding Storage Devices Upgrading System Unit contains drive bays
Floppy Disks are Portable Zip disks (Iomega): 100 and 250 MB Super. Disks (Imation): 120 MB 3½” disk: 1. 44 MB
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
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
DVD Technology Digital Video Disk Originally alternative to VCR 4. 7 GB Manufactured Can play CD-ROM and most CDRs 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 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, 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 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 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
Keyboards
Peripherals Device driver software on CD Plug and Play (Pn. P)
Tech. Talk: Windows 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 Why Recycle Computers?
Computer Hardware End
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