Definition of Computers
History of Computers
Generations of Computers
Characteristics of Computer
Types of Computers
Architecture of a Computer System
What is BIOS (basic input/output system)?
Input
Output
Computer Memory
Random Access Memory (RAM)
Read Only Memory (ROM)
Motherboard
Memory Units
Hardware
Software
Languages & Packages
Computer is an electronic
machine that makes performing any task very easy. In computer, the CPU executes
each instruction provided to it, in a series of steps, this series of steps is
called Machine Cycle, and is repeated for each instruction. One machine cycle
involves fetching of instruction, decoding the instruction, transferring the
data, executing the instruction.
Computer
system has five basic units that help the computer to perform operations, which
are given below:
1.Input Unit:
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 perform following tasks:
· 1. Accept the data and instructions from the
outside environment.
· 2. Convert it into machine language.
· 3. Supply the converted data to computer
system.
2. Output Unit:
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
This unit holds the data and
instructions. It also stores the intermediate results before these are sent to
the output devices. It also stores the data for later use.
The storage unit of a computer system can be divided into two
categories:
1. Primary Storage:
This 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.
2. Secondary Storage:
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 etc.
4. Arithmetic Logical Unit:
All the calculations are performed in ALU of the computer system. The
ALU can perform basic operations such as addition, subtraction, division,
multiplication etc. Whenever calculations are required, the control unit
transfers the data from storage unit to ALU. When the operations are done, the
result is transferred back to the storage unit.
5. Control Unit:
It controls all other units of
the computer. It controls the flow of data and instructions to and from the
storage unit to ALU. Thus, it is also known as central nervous system of the
computer.
6. CPU:
It is Central Processing
Unit of the computer. The control unit and ALU are together known as CPU. CPU
is the brain of computer system. It performs following tasks:
· 1. It performs all operations.
· 2. It takes all decisions.
· 3. It controls all the units of computer.
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Generations of Computer Types of Computers
Generations of Computer Types of Computers