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Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 2Computer Peripherals
PeripheralsDevices that are separate from the basic
computer Not the CPU, memory, power supply
Classified as input, output, and storage Connect via
Portsparallel, USB, serial
Interface to systems bus SCSI, IDE, PCMCIA
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 3Computer Peripherals
Storage DevicesPrimary memory
Expanded storageSecondary storage
Data and programs must be copied to primary memory for CPU access
Permanence of dataDirect access storage devices (DASDs)Online storageOffline storage – loaded when needed
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 4Computer Peripherals
SpeedMeasured by access time and data
transfer rate Access time: average time it takes a
computer to locate data and read itmillisecond = one-thousandth of a second
Data transfer rate: amount of data that moves per second
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 5Computer Peripherals
Hierarchy of StorageDevice Throughput Rate
CPU Registers
Cache Memory (SRAM) 15 to 30 nanoseconds
Conventional Memory (DRAM) 50 to 100 nanoseconds
Expanded Storage (RAM) 75 to 500 nanoseconds
Hard Disk Drive 10 to 50 milliseconds 600 to 6,000 KB/sec
Floppy Disk 95 milliseconds 100 to 200 KB/sec
CD-ROM 100 to 600 milliseconds 500 to 4,000 KB/sec
Tape .5 and up seconds 2,000 KB/sec (cartridge)
Typical Access Times
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 6Computer Peripherals
Secondary Storage DevicesHard drives, floppy drives
CD-ROM and DVD-ROM drivesCD-R, CD-RW, DVD-RAM, DVD-RWTape drivesNetwork drives
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 7Computer Peripherals
Magnetic DisksConsist of one or more flat, circular
platters made of glass, metal or plastic and coated with a magnetic substance.
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 8Computer Peripherals
Magnetic Disks (cont.)Track – circle
Cylinder – same track on all plattersBlock – small arc of a trackSector – pie-shaped part of a platterHead – reads data off the disk
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 9Computer Peripherals
Magnetic Disks (cont.)Head crashNumber of bits on each track is the same!
Denser towards the center.CAV – constant angular velocity
Spins the same speed for every trackHard drives – 3600 rpm – 7200 rpmFloppy drives – 360 rpm
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 10Computer Peripherals
A Hard Disk Layout
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 11Computer Peripherals
Cutaway of a floppy disk
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 12Computer Peripherals
Locating a Block of DataAverage seek time: time
required to move from one track to another
Latency: time required for disk to rotate to beginning of correct sector
Transfer time: time required to transfer a block of data to the disk controller buffer
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 13Computer Peripherals
Magnetic DisksData Block Format
Interblock gapHeaderDataFormatting disk
Disk InterleavingDisk Arrays
RAID – mirrored, striped
Disk Interleaving
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 14Computer Peripherals
RAID (striping)
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 15Computer Peripherals
RAID (mirroring)
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 16Computer Peripherals
Magnetic TapeOffline storageArchival purposesDisaster recovery
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 17Computer Peripherals
QICCan hold 120 MB to 25 GB of
uncompressed data.
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 18Computer Peripherals
DATData on DAT cartridges are
very tightly packed, using a read/write head that rotates at a high speed to pack the tape much more tightly with data.
Very tiny but have capacities of 2GB and up.
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 19Computer Peripherals
Optical StorageA direct access disk written and read by
light. CD, CD-ROM, DVD-ROM and DVD-Video are read-only optical disks that are recorded at the time of manufacture and cannot be erased.
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 20Computer Peripherals
Types of Optical StorageCD-ROMDVD-ROMWORMMagneto optical disks
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 21Computer Peripherals
CD-ROMRead-only removable medium with large
data storage capacity. Data storage is similar to magnetic disk. Laser beam is reflected off the pitted
surface of the disk as a motor rotates the disk.
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 22Computer Peripherals
Layout: CD-ROM vs. Standard Disk
CD-ROM Hard Disk
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 23Computer Peripherals
DVD-ROMSimilar to the CD-ROM technology.Uses laser with a shorter light wavelength
to allow tighter packing of the disk.Total capacity: 17GB
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 24Computer Peripherals
WORM DisksWrite-once-read-many timesSimilar to the CD-ROM technologyMedium can be altered by using a medium-
powered laser to blister the surfaceData stored in concentric tracks, sectored
like a magnetic disk
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 25Computer Peripherals
Magneto-Optical DisksCombine optical and magnetic disk
technology. Share advantages of optical disk:
capacity, reasonable cost & removabilitytogether with the read/write capability of magnetic disks.
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 26Computer Peripherals
Magneto-Optical Disks (cont.)May be stored near magnets.Limitation: have a much longer seek time
& a slower transfer rate than magnetic disks.
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 27Computer Peripherals
Magneto-Optical Disks (cont.)
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 28Computer Peripherals
DisplaysImages made up of thousands of individual
pixels or picture elementPixel: The smallest addressable unit on a
display screen or bitmapped image. Screens are rated by their number of
horizontal and vertical pixels 1024x768 means 1024 pixels are displayed
in each row, and there are 768 rows (lines).
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 29Computer Peripherals
Simplest Pixel Representation
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 30Computer Peripherals
Display ScreenScreen size: measured
diagonallyResolution: minimum
identifiable pixel size
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 31Computer Peripherals
Displays Screen (cont.)How to select a PC display screen:
Acceleration and multimedia Monitor size and resolutionLCD or CRT
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 32Computer Peripherals
Acceleration & MultimediaPlacing drawing functions into the circuits
of the display adapter speeds up rendering on screen.
Adding graphics accelerator & video accelerator cards
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 33Computer Peripherals
Acceleration & Multimedia
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 34Computer Peripherals
Monitor size & resolutionStandard resolutions:
640x480800x600
1024x7681280x10241600x1200
The higher the resolution, the more material is viewable on screen.
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 35Computer Peripherals
Displays Screen
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 36Computer Peripherals
Color and DisplaysPixel color is determined by intensity of 3 colors
– Red Green Blue or RGBRGB: The computer's native color space.It is also the color system for capturing images
and displaying them. Human eyes are sensitive to red, green and
blue, and all colors are perceived as a combination of the R, G and B.
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 37Computer Peripherals
CRT Cathode Ray Tube
A vacuum tube used as a display screen in a computer monitor or TV.
The viewing end of the tube is coated with red, green and blue phosphors dots, which emit light when struck by electrons.
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 38Computer Peripherals
CRT
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 39Computer Peripherals
Raster scanDisplaying or capturing a video image line by line from
left to right.
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 40Computer Peripherals
LCD – Liquid Crystal DisplayA display technology that uses rod-shaped
molecules (liquid crystals) that flow like liquid and bend light.
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 41Computer Peripherals
LCD (cont.)
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 42Computer Peripherals
Plasma DisplayGas discharge displayUses tiny cells lined with phosphor that are
full of inert ionized gas
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 43Computer Peripherals
Plasma Display (cont.)
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 44Computer Peripherals
PrintersDots vs. pixels
300-2400 dpi vs. 70-100 pixels per inchDots are on or off, pixels have intensities
TypesTypewriter / Daisy wheels – obsoleteDot matrix – usually 24 pins, impact printingInkjet – squirts heated droplets of inkLaserjetThermal wax transferDye Sublimation
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 45Computer Peripherals
PrintersGeneral Categories
Serial Printers (Character Printers)Line PrintersPage Printers
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 46Computer Peripherals
Serial PrinterPrints one character at a time moving
across the paper.Eg. serial dot matrix printer, with speeds
ranging from 200 to 400 cps (90 to 180 lines per minute)
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 47Computer Peripherals
Dot MatrixUses hammers and a ribbon to form
images out of dots. Forms characters and graphics by
impacting a ribbon and transferring dots of ink onto the paper.
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 48Computer Peripherals
Dot Matrix (cont.)
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 49Computer Peripherals
Line PrinterPrint a line at a time from approximately
400 to 2,000 lpmEg. Line Matrix printer
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 50Computer Peripherals
Line Matrix
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 51Computer Peripherals
Line Matrix (cont.)
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 52Computer Peripherals
Page PrinterPrints a page at a time from four to more
than 800 ppm. Eg. Laser Printer
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 53Computer Peripherals
Laser PrinterUses a laser and the electrophotographic
method to print a full page at a time. The laser "paints" a charged drum with
light, to which toner is applied and then transferred onto paper.
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 54Computer Peripherals
Laser Printer
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 55Computer Peripherals
Other PrintersInk jetDye sublimationThermal Wax transfer
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 56Computer Peripherals
Ink JetPropels droplets of ink directly onto the
medium. Makes use of an ink jet cartridge
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 57Computer Peripherals
Ink Jet Printer
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 58Computer Peripherals
Dye sublimation printerProduces continuous-tone images that
look like photographic film. Also called a "thermal dye printer”.The print cartridge contains a cellophane
ribbon with panels of dye the same size as the page to be printed.
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 59Computer Peripherals
Dye sublimation printer (cont.)
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 60Computer Peripherals
Dye Sublimation Printer
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 61Computer Peripherals
Thermal wax transfer printerUses the same printing mechanism as a
dye sublimation printer.Instead of using a dye, it melts dots of
wax-based ink that adhere to almost any kind of stock, from ordinary paper to complex synthetics and film.
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 62Computer Peripherals
Thermal wax transfer printer
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 63Computer Peripherals
Other Computer PeripheralsScanners
Flatbed, sheet-fed, hand-heldLight is reflected off the sheet of paper
User Input DevicesKeyboard, mouse, light pens, graphics tablets
Communication DevicesTelephone modemsNetwork devices
Englander, The Architecture of Computer Hardware and Systems
Software An Information Technology Approach, 3rd ed., 2003 64Computer Peripherals
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