The document outlines the fundamental functioning of computer systems, including their primary components such as input units, central processing units, and output units. It discusses the concepts of data and information, detailing how computers operate in the IPO (Input-Process-Output) cycle to convert raw data into meaningful information while highlighting their strengths, such as speed, reliability, versatility, and accuracy. Additionally, it addresses weaknesses like lack of decision-making ability and learning power, emphasizing that computers require user instructions to operate.

1. ICT SKILLS - 1
BASICS OF COMPUTER SYSTEM
INFORMATION TECHNOLOGY(402)
CLASS: IX

2. INDEX
What is a computer?
Functioning of the Computer system
Characteristics of computer
Functional components of Computer system

3. Computer is an electronic device which accepts data and instructions, process it
and produces a useful output.
What is data?
What is information?
It is used for the raw facts which need to be
processed by the computer.
It is a processed form of data. In other words means
processed and meaningful form of data.

4. As you know that computer works in the IPO cycle to convert the raw
data into a useful information.
Input Process Output
Accept data
and
instructions
Manipulates
data as per
instructions
Produced
desired
outputs

5. A computer, mainly, has four functions
Accept Data:- Input
Main Unit
INPUT UNIT
(Input devices)
OUTPUT UNIT
(Output devices)
CENTRAL PROCESSING UNIT
Control Unit
Arithmetic and
Logical Unit
In the first stage it
reads data and
instructions by
input unit.

6. A computer, mainly, has four functions
Accept Data:-
Processes Data:-
Input
Processing
Main Unit
INPUT UNIT
(Input devices)
OUTPUT UNIT
(Output devices)
CENTRAL PROCESSING UNIT
Control Unit
Arithmetic and
Logical Unit
Second stage is
performed by its
Central Processing
Unit.

7. A computer, mainly, has four functions
Accept Data:-
Processes Data:-
Produce Output :-
Input
Processing
Output
Main Unit
INPUT UNIT
(Input devices)
OUTPUT UNIT
(Output devices)
CENTRAL PROCESSING UNIT
Control Unit
Arithmetic and
Logical Unit
Third stage is
performed by
output unit

8. A computer, mainly, has four functions
Accept Data:-
Processes Data:-
Produce Output :-
Stores Result:-
Input
Processing
Output
Storage
Main Unit
INPUT UNIT
(Input devices)
OUTPUT UNIT
(Output devices)
CENTRAL PROCESSING UNIT
Control Unit
Arithmetic and
Logical Unit
All this done with the help of
memory.

9. Input Unit:
It is responsible for providing the information in the computer and is
performed by Input unit.
For this purpose, standard input devices such as keyboard, mouse,
scanner etc.

10. Output Unit:
It is responsible for displaying data input to computer or the
processed data in human readable form. The standard output
devices are as monitor, printer speaker etc.

11. Processing Function:
This is responsible for carrying out the given instructions on given data.
It is performed by CPU(Central processing unit)
It is responsible for carrying out arithmetic instructions e.g.: +, -, x, / or
Logical instructions >, <, = etc.
This unit is responsible for controlling the execution of
instructions.
This memory available to CPU to store data and instructions being
processed.
ALU( Arithmetic and Logic Unit):
CU(Control Unit):
Primary Memory:

12. Strengths of Computers:
SPEED:
storage:
Computers are much faster than human beings it can process
millions of instructions per seconds. The speed of a computer is
measured in Megahertz(MHz) and Gigahertz(GHz).
Computer can store a large amount of information in a very limited
space.

13. Strengths of Computers:
RELIABILITY:
VERSATILITY:
Computer being a machine does not suffer from tiredness or lack of
concentration and can work continuously for hours without making any
mistake. Thus it is more reliable than human being.
Computers can perform repetitive jobs efficiently. It can be used to
perform various types of jobs very efficiently ranging from complex
scientific research to flying an aircrafts.

14. Strengths of Computers:
ACCURACY:
The computer accuracy is consistently very high.If the data and
instructions given by the user are error free and the hardware does
not malfunction, it always give 100% accurate results.

15. Weaknesses of Computers:
Lack of decision-making power:
Iq zero:
No learning power:
Computer cannot take any decision of its own. They do not posses this power
which is a great asset of human beings. Computer decides only with the help of
instructions given by the user.
Computer are dumb machines with zero IQ.A computer cannot do anything of
its own and it needs user’s instructions to do some work.
Computer lacks the learning power and its does not use any of its previous
experience while doing the same things.