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Workshop on Computer Hardware and Network
Notes be clearly understood. For convenience, the hardware of a computer can be classified in the
following categories:
1. Input Devices
2. Output Devices
3. Central Processing Unit (CPU)
4. Memory or Storage
5. Motherboard
Let us discuss each of these hardware components:
1. Input Devices: The form in which data is available to a user is not always in the same form
as is accepted by computer hardware. Input devices are hardware equipment that receive
data and instructions from users, convert the data and instructions into a form that can be
processed by the computer and passes the same to the computer. Hence, if you have to
enter employees’ names into the computer you do not have to write it on a piece of paper
and shove the paper inside the computer. You will need some input device for this.
Example: A keyboard is an example of input device.
2. Output Devices: The result, produced by a computer after processing, is not always in user
readable form. An output device is hardware equipment that translates this non-readable
result into a form understood by the users.
Example: A VDU (Visual Display Unit) or monitor is an example of output device.
3. Central Processing Unit (CPU): Central processing unit is to computer what brain is to our
body. It is the master organ of a computer. No computer can exist without a CPU. It is
composed of two simpler hardware units - Arithmetic Logic Unit (ALU) and Control Unit
(CU). CU controls all the activities of other hardware units while ALU performs all the
calculations. Computer CPUs are very fast in their calculations and swift in control.
4. Memory or Storage: This hardware is the place where a computer stores all the data and
instructions given to it. The results of the processing are also stored here. A computer has
many types of memories. Some memories are directly connected to the CPU and are
extremely fast as far as storage and retrieval of data is concerned. These memories are
called primary memory - RAM (Random Access Memories) and ROM (Read Only
Memories) belong to this category of memories. The CPU takes data and instructions
stored only in the primary memories.
Notes Primary memories are also of various types. The one that looses its contents when
power is switched off is known as volatile memory such as RAM. Some memories retain
the data and instructions stored on them even after the power is switched off such as ROM.
These memories are known as non-volatile memories.
Secondary storage devices are placed outside the system unit and can be carried from one
system to another allowing portability of data and instructions. Floppy disks or diskettes,
hard disks and CD-ROM are some of the secondary storage devices. Input devices, output
devices and secondary storage devices are not directly connected to the CPU and hence are
known as peripheral devices or simply peripherals.
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