Computer Peripheral
- 2. Content
Device Drivers
Plug-n-Play Devices
Input Devices
Output Devices
Storage Devices
Network Devices
Communication Device
References
- 3. Device Drivers
A program to tell the system software how to
work with that piece of hardware
Some common device drivers are built in the
system software (Operating System) e.g.
keyboard and mouse drives
- 4. Plug-n-Play Devices
Devices designed such that Windows can
detect them, install and configure the device
driver automatically
For non plug-n-play devices, we have to install
and configure the device driver manually.
- 6. Input Devices (2)
Pointing Devices
Mouse, trackball, touch pad, light pen, digitizer
Touch screen
- 7. Input Devices (3)
Scanning devices
Image scanner
Fax machine – scan image to bitmap
Bar code scanner – scan Universal Product Code
(UPC)
Magnetic ink character scanner (MICR)
Optical character scanner (OCR)
Optical mark scanner (OMR)
- 8. Input Devices (4)
Voice Input Device
Microphone – to receive the sound signal
Sound card – to convert the sound signal to digital
form
Use speech recognition software to recognize
human speech
- 9. Input Devices (5)
Handwriting Recognition Device
Need handwriting recognition software
Called natural input
Slow inputting speed
- 10. Output Devices (1)
Visual Display Unit (VDU)
Commonly called monitor
2 common types of monitor
CRT (Cathode Ray Tube) monitor
High radiation and bulky
LCD (Liquid Crystal Display) monitor
No radiation and slim
- 11. Output Devices (2)
Printer – to produce hard copy
Laser printer
to produce high quality output
resolution up to 2400 dpi (dot per inch)
use carbon toner, usually for black and white
printout, colour is very expensive
- 12. Output Devices (3)
Inkjet printer
produce good quality colour output
resolution up to 1440 dpi
use ink droplets to compose the image
The printer is much cheaper than laser printer but
the ink is very expensive
- 13. Output Devices (4)
Dot matrix printer
Use impact principle
Can print multiple (carbon) copies at a time,
usually use in printing invoices
The ink ribbon is cheap
Poor quality of printout
- 14. Output Devices (5)
Plotter
Drawing high quality image, use colour pens, can
draw smooth curves
Can print on large paper size, use roll of paper
To draw posters and maps
Use in CAD (Computer Aided Design)
- 15. Output Device (6)
Voice output devices
Sound card, to convert computer signals to sound
Speakers, to amplify the sound output
- 16. Storage Devices (1)
Floppy Disk (Diskette)
A flexible plastic circular disc
Packed in a plastic square jacket
Formatted to 1.44MB
Divided to many circular tracks
Each track is divided to many sectors
Use magnetic technology to store data ‘0’ or ‘1’
Random access
Slow accessing speed
- 17. Storage Devices (2)
Hard Disk
High storage capacity, over 100 GB
Hard metallic surface
Consists of several metallic disks
Data are stored in cylinder (a deck of tracks)
(see p.86)
Use magnetic technology
Very high access speed
Random access
- 18. Storage Device (3)
Optical disk
CDROM, DVDROM, CDRW, DVDRW
Use optical technology, laser reflection on pits
‘1’ will reflect the laser beam while ‘0’ does not
High storage capacity, 700 MB for a CDROM,
17GB for a DVDROM
Random access
High access speed
- 19. Storage Device (4)
Tape
Cheap
Sequential access
Use magnetic technology
Ideal for backup data, we need to backup and restore all data
High storage capacity
Slow access speed
Group of records are stored in a block
Inter-block gaps are needed for stopping and starting the
read/write head.
- 20. Storage Device (5)
Other Storage devices – can be read/write
Removable disks -Zip disk(100/250MB),
superdisk(120MB), Jazz disk(1GB)
MO disk
Flash memory cards – compact flash, smart
media and memory stick, commonly used in
digital camera
- 21. Network Devices (1)
Network Interface Card (NIC) (LAN card)
Connection between the network and the computer bus
Have built-in transceiver, for data transmitting and receiving
Usually 100 MB/s
Wireless LAN card
Usually 11 MB/s
Work within the distance range, and no blocking in between.
- 22. Network Devices (2)
Connectors
RJ-45 telephone jack connector
For connecting twisted pairs LAN cable
BNC connector
For connecting coaxial cables
- 23. Network Device (3)
Terminators
Use in bus network, to prevent signal rebounce
and echo at the ends of bus.
- 24. Network Device (4)
Hub
To connect the workstations within a room on
same floor
Switch
To connect the workstations for different floors in
a building, it is faster and more efficient than a
Hub.
Router
To connect different LANs together to form a
Wide Area Network (WAN)
- 25. Network Device (5)
Repeater
When a network spans a long distance, the signal
weaken, repeater is used to reproduce the signal.
Exchange
To boost the signals along the network path for a
Wide Area Network.
- 26. Network Device (6)
Computer
Different computers play different roles on a
network
Server
Provide services to other computers connected to
the network, usually have higher processing
power and larger storage capacity.
Workstation
The computers connected to the network but not
act as a server.
- 27. Network Device (7) - Servers
File server
control the sharing and access of files over the network, must
have a huge storage capacity.
Print server
Manage the print jobs from different computers to different
network printers, and manage the print queues.
Web server
To host a web site and publish web pages on the web,
support HTML, Java script, CGI, PHP and ASP web
languages
Email server
To store, send and receive emails over the Internet
Internet server
To provide Internet access
- 28. Communication Device
Modem - Modulator-demodulator
It transforms digital signals of computer to analog
signals to be transmitted through telephone lines.
(Modulation)
It also transforms analog signals back to digital
signals for the computer that receives the signals.
(Demodulation)
- 29. Data/Signal Rate
Data Rate
Refer to the no. of bits per second sent
Signaling Rate (Baud Rate)
Refer to the no. of signals per second sent
Each signal may consists of several bits e.g.
101
Bandwidth
The frequency range of a particular media
is directly proportional to the data rate