The computer performs basically five major operations of functions
irrespective of their size and make. These are 1) it accepts data or
instruction 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 into the computer system.
Input unit connects the external environment with internal
computer system. It provides data and instructions to the computer system.
Commonly used input devices are keyboard, mouse, magnetic tape etc.
Input unit performs following tasks:
• Accept the data and instructions from the outside
environment.
• Convert it into machine language.
• Supply
the converted data to computer system.
- Control Unit (CU): The process of
input, output, processing and storage is performed under the supervision
of a unit called 'Control Unit'. It decides when to start receiving data,
when to stop it, where to store data, etc. It takes care of step -by-step processing
of all operations inside the computer.
- Memory Unit: Computer is used to
store data and program. There are two classes of memory devices:- Primary
and Secondary
Primary memory is used to store the data which is being
currently executed. It is used for temporary storage of data. The data is lost,
when the computer is switched off. RAM is used as primary storage memory.
The secondary memory is slower and cheaper than primary
memory. It is used for permanent storage of data. Commonly used secondary
memory devices are hard disk, CD, Floppy Disk, Magnetic
Tapes etc.
- Arithmetic Logic Unit (ALU): The
major operations performed by the ALU are addition, subtraction,
multiplication, division, logic and comparison.
- Output: This is the process of
producing results from the data for getting useful information.It connects the internal system
of a computer to the external environment. It provides the results of any
computation, or instructions to the outside world. Some output devices are
printers, monitor etc.
The ALU and the CU of a
computer system are jointly known as the central processing unit (CPU). The
heart of the computer system is the Processor unit.
PERIPHERAL DEVICES:
Peripheral devices are connected to the computer externally.
These devices are used for performing some specific functions. Peripheral
devices are as follows:
1. Input Devices
2. Output Devices
3. Other Peripherals
INPUT
DEVICES:
Input
devices accept data and instructions from the user. Following are the examples
of various input devices, which are connected to the computer for this purpose.
1.
Keyboard
2.
Mouse
3.
Light
Pen
4.
Optical/magnetic
Scanner
5.
Touch
Screen
6.
Microphone
for voice as input
7.
Track Ball
OUTPUT DEVICES:
Output devices return processed data that is
information, back to the user. Some of
the commonly used output devices are:
1.
Monitor (Visual Display Unit)
2.
Printers
3.
Plotter
4.
Speakers
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