Computer Basics
Basic Computer Operations
Arithmetic logical unit
Control unit
Central processing unit
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A computer as shown in Figure performs basically
five major 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.
We discuss below each of these operations.
Input
This is the process of
entering data and
programs in to the computer system.
The 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.
Fig - Basic computer operation
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:
1) All data and instructions are stored here before and after processing.
2) Intermediate results of processing are also stored here.
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.
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.
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 in side the computer.
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.
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.
The next component of computer is the Control Unit, which acts like the
supervisor seeing that
things are done in proper fashion. 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 .
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.
Hardware
Software
Fig - Computer Architecture