Slide 1 © 2008 Prentice-Hall, Inc.. Hardware Basics: Peripherals Slide 2 © 2008 Prentice-Hall, Inc.

Slide 1© 2008 Prentice-Hall, Inc.

Hardware Basics: Peripherals


List several examples of input devices and explain how they can make it easier to get different types of information into the computer.

List several examples of output devices and the explain how they make computers more useful.

Explain why a typical computer has different types of storage devices.

Diagram how the components of a computer system fit together.


KeyboardThe most familiar input

deviceUsed to enter letters, numbers

and special characters


Standard keyboard Ergonomic

keyboards To address

possible medical problems

Wireless keyboard Folding keyboards

Used with palm-sized computers

One-handed keyboards

Keyboards printed on membranes


Pointing Devices Mouse Touchpad Pointing stick Trackball Joystick Graphics tablet Touch screenStylus


Reading ToolsRead marks

representing codes specifically designed for computer input


Optical-mark readers Magnetic-ink character readers Bar-code readers Pen scanners Tablet PC Smart whiteboard Radio Frequency Identification

Readers (RFID)


Digitizing the Real World

Scanners capture and digitize printed images.

Flatbed Slide Drum Sheet-fed


Digital cameraSnapshots captured as

digital imagesDigital images stored as

bit patterns on disks or other digital storage media


Video digitizer Capture input from a:

Video cameraVideo cassette recorder or television

Convert it to a digital signalStored in memory and displayed on computer screens

Videoconferencing People in diverse locations can

see and hear each other Used to conduct long-distance meetings

Video images transmitted through networks


Audio digitizers Digitize sounds from

Microphones Other input devices

Digital signals can be Stored Further processed with

specialized softwareA digital signal processing chip compresses the stream of bits before it is transmitted to the CPU.


Speech recognition software Converts voice data into words that

can be edited and printed


Sensors Designed to monitor physical conditions

Temperature, humidity, pressure Provide data used in:

Robotics Environmental climate control Weather forecasting Medical monitoring Biofeedback Scientific research


Screen Output A monitor or video display terminal

(VDT) displays characters, graphics, photographic images, animation and video.

Video adapter—connects the monitor to the computerVRAM or video memory—a special portion of RAM to hold video images

The more video memory, the more picture detail is displayed.


Monitor size: Measured as a diagonal line across the screen

Resolution: The number of pixels displayed on the screen Pixels (or picture elements): tiny dots that compose a pictureThe higher the resolution, the closer together the dots.

Image quality is affected by resolution and color depth (or bit depth).

Color depth refers to the number of different colors a monitor displays at one time.


Monitor classes CRTs (cathode-ray tubes) LCDs (liquid crystal displays)

• Overhead projection panels • Video projectors• Portable computers


Paper OutputPrinters produce paper output or hard copy. Two basic groups of printers:

Impact printers•Line printers •Dot-matrix printers


Non-impact printers•Laser printers

−Laser beam reflected off a rotating drum to create patterns of electrical charges−Faster and more expensive than dot matrix printer−High-resolution output

•Inkjet printers −Sprays ink onto paper to produce printed text and graphic images−Prints fewer pages/minute than laser printer−High-quality color; costs less than laser printer


Multifunction printer or MFP combines a scanner,

printer and a fax modem.A plotter can produce large, finely scaled engineering

blueprints and maps.


Fax Machines and Fax ModemsFacsimile (fax) machine

Sending: •scans each page as an image•converts the image into a series of electronic pulses•sends those signals over phone lines to another fax

Receiving: •uses the signals to reconstruct the image•prints black-and-white facsimiles or copies of the originals

Fax modem Connect from PC to fax machine via modem and phone line


Output You Can HearSound card

Enables the PC to:•Accept microphone input

•Play music and other sound through

speakers or headphones

•Process sound in a variety of waysSynthesizers

Used to produce music, noise


Controlling Other Machines

Output devices take bit patterns and

turn them into non-digital movements.

Robot armsTelephone switchboardsTransportation devicesAutomated factory equipmentSpacecraftForce feedback joystick


Rules of Thumb: Ergonomics and Health

Choose equipment that’s ergonomically designed.Create a healthy workspace.Build flexibility into your work environment.Rest your eyes.Stretch to loosen tight muscles.Listen to your body.Seek help when you need it.


Magnetic TapeCan store large amounts of information

in a small space at a relatively low costLimitation: sequential data accessUsed mainly for backup purposes


Magnetic DisksRandom data accessFloppy disks

Provide inexpensive, portable storageHard disks

Non-removable, rigid disks that spin continuously and rapidly Provide much faster access than a floppy disk

Removable media (Zip & Jaz disks) Provides high-capacity portable storage

Slide 27

Optical DisksUse laser beams to read and write bits of information on the disk surface

Not as fast as magnetic hard disksMassive storage capacity Very reliable


CD-ROM Optical drives that read CD-ROMs

CD-R WORM media (write-once, read many)

CD-RW Can read CD-ROMs and write, erase and rewrite data onto CD-R & CD-RW disks


DVD (Digital Versatile Disks)Store and distribute all kinds of dataHold between 3.8 and 17 gigabytes of information

DVD-ROM drives Can play DVD movies, read DVD data disksRead standard CD-ROMs, and play audio CDsRead-only: can’t record data, music, or movies

DVD-RAM drives Can read, erase, and write data (but not DVD video) on multi-gigabyte DVD-R (but not CD-R or CD-RW) media


Solid-State Storage DevicesFlash memory is an erasable memory chip:

Sizes range from 16 MB to 1 GBCompact alternative to disk storageContains no moving partsDesigned for specific applications such as storing pictures in digital camerasLikely to replace disk and tape storage


Personal Computer Design ClassesTower systems

Tall, narrow boxes, generally have more expansion slots and bays than

other designs

Flat desktop systems Designed to sit under the monitor like a platform

All-in-one systems (like the iMac) Combine monitor and system unit into a single housing


Laptop computers Include all the essential components, including keyboard and pointing device,

in one compact box


Ports and Slots RevisitedThe system or motherboard includes several standard ports:

Serial Port for attaching devices that send/receive messages one bit at a time (modems)Parallel Port for attaching devices that send/receive bits in groups (printers)Keyboard/Mouse Port for attaching a keyboard and a mouse


Other ports are typically included on expansion boards rather than the system board:

A video port is used to plug a color monitor into the video board.Microphones, speakers, headphones, MIDI ports are used to attach sound equipment.An SCSI port allows several peripherals to be strung together and attached to a single port.A LAN port uses faster connections to a local-area network (LAN).


Expansion Made EasyWith the PC open architecture and the introduction of new interfaces, you can hot swap devices.

USB (Universal Serial Bus) transmits a hundred times faster than a PC serial port

Firewire (IEEE 1394) can move data between devices at 400 or more megabits per second. The high speed makes it ideal for data-intensive work, like digital video.

FireWire 800, which offers 800 Mbps transfer speeds, was recently introduced on high-end Macintosh systems.


Putting It All TogetherA typical computer system might have several different input, output, and storage peripherals—the key is compatibility.Networks blur the boundaries between computers.Networked computers may have access to all the peripherals on a system.The computer is, in effect, just a tiny part of a global system of interconnected networks.


Tomorrow’s Storage

Smaller disks that hold moreA single electron memory chip the size of a thumbnail that can store all of the sounds and images of a full-length feature film

Tomorrow’s Output

Flat-panel screens replacing desktop CRTs

Retinal displays that work without a screen


Tomorrow’s Input: Sensors

More sophisticated devices will serve as eyes, ears, and other types of sense organs for computer networks.


Peripherals allow computer to communicate with the outside world and store information for later use information.

The most common input devices today are the keyboard and the mouse. A variety of other input devices can be connected to the computer.

Output devices perform the opposite function: They accept strings of bits from the computer and transform them into a form that is useful or meaningful outside the computer.


Storage devices are capable of two-way communication with the computer. Because of their high-speed random access capability, magnetic disks are the most common forms of storage on modern computers.

Network connections make it possible for computers to communicate with one another directly.


Slide 42

Slide 43

Slide 1 © 2008 Prentice-Hall, Inc.. Hardware Basics: Peripherals Slide 2 © 2008 Prentice-Hall, Inc.

Documents