2. Different types of Computer
1. Main Frame Computers
A main frame computer is a large system usually requiring
specialized, dedicated room with its own air conditioning system
and power supply. It is usually used by large organizations for
critical or sensitive applications which rely on very large volumes of
data such as country – wide credit card transactions and billing
information, census, aerospace research, ERP and banking
institutions.
4. 2. Supercomputers
a supercomputer is a a computer that takes the lead in
terms of processing capacity, particularly speed of calculation. The
processing power of supercomputer is usually needed for heavy
calculation - intensive tasks such as the consequences of pollution
and global warning, molecular modeling, engineering simulations
such as the study of airplane models in wind tunnels, nuclear
research, cryptanalysis and other specialized applications.
3. Minicomputers
a class of multi – user computer which occupied the middle
range of the computing spectrum, in between the largest multi –
user systems or mainframe computers and the smallest single –
users systems like microcomputers or personal computers.
7. 4. Microcomputers
is a single – user computer which is small enough to fit ion
a desk or under a table.
8. Types of Microcomputer
1. PDA (Personal Digital Assistant)
A hand – held computing device usually used to manage
appointments, schedules and contacts.
2. Hand – held (HPC)
A type of microcomputer that is small enough to e held in
your hand.
11. 3. Laptop
A small, portable computer which integrates the display
with its cover (a.k.a clamshell design) with the keyboard embedded
in the actual body of the computer.
4. Macintosh Computers (MAC)
is popular model of computer which was originally
developed by Apple Computer in 1984. Apple was the first
commercially successful personal computer to use graphical user
interface (GUI) which uses windows, icons and a mouse to make it
easy for beginners to use a computer.
5. Desktop / Personal Computer
refers to any type of small, single – user computer which
usually runs Microsoft Windows and can be found in millions of
homes and offices around the world.
17. 2. The Mouse
Is a palm- sized input device which is designed to sit on
you desktop. Using one hand, you move the mouse on your desk
which in turn causes the pointer on your screen to move in unison
with your hand’s motion.
18. 3. Glidepad
also known as a touch pad, this is touch sensitive pad for
controlling the cursor. The user glides a finger across the pad’s
surface and the cursor follows the finger movement.
19. 4. Game Controller
a joystick is a classic example of a game controller for the
computer.
20. 5. Touch Screen
a special type of monitor which allows you to click objects
on the screen by touching the screen with your finger.
22. Digital Cameras
a type of camera that can directly capture and store
pictures in digital format.
23. 8. Barcode Reader
also called a barcode scanner or point – of – sale (POS)
scanner, it is a hand – held or stationary input device used to
capture and read information contained in a barcode.
24. 9. Thumb Mouse
this operated on the same principle as a regular mouse but
the ball remains stationary on top of the device.
25. 10. Scientific Probe and Sensor
these are special devices which can captures various
types of data like pressure or temperature and convert it into digital
format for your computer to use.
26. 11. Remote Control
it is often used to control a device by sending radio or
infrared signals over short distances.
28. 1. Monitor
It is like a television or cathode ray tube (CRT) that displays data from
your computer. An LCD monitor is flat and takes up much less space than a
conventional CRT monitor.
29. 2. Printer
It is a device that prints images or pictures created on the computer
on paper. The printed output from the printer is called hardcopy.
30. 3. Plotters
Used for printing bug posters, architectural drawings and billboards.
They can be pen – based or ink – jet based.
31. 4. Projector
Displays the image on a wall – sized screen. It is best for giving
lectures to a big crowd so that everybody can see the presentation properly.
32. 5. Voice Synthesizer
Is used to mimic the human voice. Voice synthesizers can interpret
text and convert into tones which sound like human speech.
33. 6. Control Devices / Robots
It lets you control a machine from a distance. Control devices also
have tiny microprocessors inside to work independently or to allow you to
program them special functions.
7. Braille Translator
With the device any information from any word processor on the
computer can turned into Braille at the touch of a button on the devices
34. Selecting A Personal Computer
1. Consider who will use the computer and the kind of work to be done.
2. Consider the volume of work that will be done on the computer and the size
of the files that you’ll be creating. A gaming computer needs more graphics
processing power to run the newer games.
3. Set a budget before you shop. You have to set a practical limit to avoid
overspending for your PC.
4. Consider carefully whether a desktop or a laptop computer is more suited to
your needs and work style.
5. Consider what brand might be best for you.
35. FACTORS THAT AFFECT COMPUTER PERFORMANCE
1. The computer must be free from virus. Trojans, spyware and other malware.
Run a virus scan own your computer regularly.
2. The correct version of windows must be used. Computer parts should meet
the requirements of the software installed on your computer, including the CPU
speed, the amount of RAM or memory.
3. Software must have proper device drivers installed for the hardware that is
connected to the computer.
4. The network or modem connection speed affects the performance of your
computer by speeding up internet access.
5. Power failures may also cause a lot of damage.
6. Lack of disk space and fragmented hard drive can also slow down your
computer and are also common problems.
7. Low microprocessor speed and low memory also affect the performance of
your computer.
36. Protect your computer from:
1. Temperature Extremes 2. Fire
3.Smoke 4. Dust
5. Earthquakes 6. Bugs
11. Power outrage
8. Food and Drinks
9. Water 10. Theft
7. Humidity
12. Magnetic Field