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.
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.
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.
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
1) arithmetic logical unit
2) control unit.
3) central processing unit.
Arithmetic Logical Unit 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 coordinating 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 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.
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