A computer can process
data, pictures, sound and graphics. They can solve highly complicated problems
quickly and accurately. A computer as shown in Fig. performs basically
five major computer operations or functions irrespective of their size and
make. These are
1) it accepts data or instructions by
way of input,
2) it stores data,
3) it can process data as required by the user,
4) it gives results in the form of output, and
5) it controls all operations inside a computer.
2) it stores data,
3) it can process data as required by the user,
4) it gives results in the form of output, and
5) it controls all operations inside a computer.
We discuss below each of these Computer operation
1. Input: This is the process of entering data and programs in to the
computer system. You should know that computer is an electronic machine like
any other machine which takes as inputs raw data and performs some processing
giving out processed data. Therefore, the input unit takes data from us to the
computer in an organized manner for processing.
2. Storage: The process of saving data and
instructions permanently is known as storage. Data has to be fed into the
system before the actual processing starts. It is because the processing speed
of Central Processing Unit (CPU) is so fast that the data has to be provided to
CPU with the same speed. Therefore the data is first stored in the storage unit
for faster access and processing. This storage unit or the primary storage of
the computer system is designed to do the above functionality. It provides
space for storing data and instructions.
The storage unit performs the
following major functions:
• All data and
instructions are stored here before and after processing.
• Intermediate
results of processing are also stored here.
3.
Processing: The task of performing operations like
arithmetic and logical operations is called processing. The Central Processing
Unit (CPU) takes data and instructions from the storage unit and makes all
sorts of calculations based on the instructions given and the type of data
provided. It is then sent back to the storage unit.
4. Output: This is the process of producing results from the data for getting
useful information. Similarly the output produced by the computer
after processing must also be kept somewhere inside the computer before being
given to you in human readable form. Again the output is also stored inside the
computer for further processing.
5.
Control: The manner how instructions are executed
and the above operations are performed. Controlling of all operations like
input, processing and output are performed by control unit. It
takes care of step by step processing of all operations inside the computer.
FUNCTIONAL UNITS
In order to
carry out the operations mentioned in the previous section the computer
allocates the task between its various functional units. The computer system is
divided into three separate units for its operation. They are
Arithmetic Logical Unit (ALU)
Logical Unit :After you enter data through the input device it is stored in
the primary storage unit. The actual processing of the data and
instruction are performed by Arithmetic Logical Unit. The major operations
performed by the ALU are addition, subtraction, multiplication, division, logic
and comparison. Data is transferred to ALU from storage unit when required.
After processing the output is returned back to storage unit for further
processing or getting stored.
Control Unit (CU)
The next
component of computer is the Control Unit, which acts like the supervisor
seeing that things are done in proper fashion. Control Unit is
responsible for co ordinating various operations using time signal.
The control unit determines the sequence in which computer programs and
instructions are executed. Things like processing of programs stored in the
main memory, interpretation of the instructions and issuing of signals for
other units of the computer to execute them. It also acts as a switch board
operator when several users access the computer simultaneously. Thereby it
coordinates the activities of computer’s peripheral equipment as they perform
the input and output.
Central Processing Unit (CPU)
The ALU and the
CU of a computer system are jointly known as the central processing
unit. You may call CPU as the brain of any computer system. It is just like
brain that takes all major decisions, makes all sorts of calculations and
directs different parts of the computer functions by activating and controlling
the operations.