Chapter 3 Hardware Basics: Peripherals

Keyboard

ü  The most familiar input device

ü  Used to enter letters, numbers and special characters

Standard keyboard

Ergonomic keyboards

ü  To address possible medical problems

Wireless keyboard

Folding keyboards

ü  Used with palm-sized computers

One-handed keyboards 

Keyboards printed on membranes

Pointing Devices

ü   Mouse

ü  Touchpad

ü  Pointing stick

ü  Trackball

ü  Joystick

ü  Graphics tablet

ü  Touch screen

ü  Stylus

Video digitizer

ü  Capture input from a:

ü  Video camera

ü  Video cassette recorder or television

Convert it to a digital signal

ü  Stored in memory and displayed on computer screens

Videoconferencing

ü  People in diverse locations can see and hear each other

ü  Used to conduct long-distance meetings

Video images transmitted through networks

Screen Output

Ø  A monitor or video display terminal (VDT) displays characters, graphics, photographic  images, animation and video.

q  Video adapter—connects the monitor to  

                                    the computer

q  VRAM or video memory—a special

                                    portion of RAM to hold video images

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

Fax Machines and Fax Modems

Ø  Facsimile (fax) machine

Ø  Sending:

Ø  scans each page as an image

Ø  converts the image into a series of electronic pulses

Ø  sends those signals over phone lines to another fax

Ø  Receiving:

Ø  uses the signals to reconstruct the image

Ø  prints black-and-white facsimiles or copies of the originals

Fax modem

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

Magnetic Disks

Ø  Random data access

Ø  Floppy disks

q  Provide inexpensive, portable storage

Ø  Hard disks

q  Non-removable, rigid disks that spin continuously
    and rapidly

q  Provide much faster access than a floppy disk

Ø  Removable media (Zip & Jaz disks)

Provides high-capacity portable storage

CD-ROM

q  Optical drives that read CD-ROMs

CD-R

q  WORM media (write-once, read many)

CD-RW

q  Can read CD-ROMs and write, erase and

rewrite data onto CD-R & CD-RW disks

DVD (Digital Versatile Disks)

q  Store and distribute all kinds of data

q  Hold between 3.8 and 17 gigabytes of information

DVD-ROM drives

q  Can play DVD movies, read DVD data disks

q  Read standard CD-ROMs, and play audio CDs

q  Read-only: can’t record data, music, or movies

DVD-RAM drives

q  Can read, erase, and write data (but not DVD video) on multi-gigabyte

                        DVD-R (but not CD-R or CD-RW) media