Computer
Introduction-
Computer is an electronic device, which can perform mathematical and logic operation according to a set of instruction.
The computer is capable
of accepting data (input), processing data arithmetically and
logically, producing output from the processing,
A computer is primarily
made of the Central Processing Unit (usually referred to as the computer), the
monitor, the keyboard, and the mouse. Other pieces of hardware are commonly
referred to as peripherals.
Hardware-
Hardware are those components that make up the
computer. Like as monitor, speakers,
mouse, CDROM, floppy
drive, keyboard, CPU, RAM,
Processor, etc. Each piece plays a role in the operation of a computer.
Software-
Software is the set of
instruction that tells the computer what to do and when to do it. The computer
uses this instruction to manipulate
data, and enhance
the proper functioning
of the hardware
components.
Software
are mostly two type
1-
System software
2-
Application
software
1-
System software
System software is general
programs written for the system which provide the environment to facilitate the
writing of application software.
2-
Application
software
Application
software are the set of programs necessary to carry out operations for a
specialized application
Component of a computer
The standard computer consists of a monitor, a keyboard, a mouse
and the system unit. One can attach accessories such as printers and scanners by
means of ports, computers are connected to other computers by means of
a network.
1.
Output unit
The function of out unit is
reveres in nature than that of the input unit. It is used to take out data,
instructions and results of computation from the central processing unit
(CPU).The output may be in the form of audio signal, video displays on screen,
discs, photofilms etc.
Common output
device are-
Monitor, printer, optical printer, floppy disc, magnetic tape etc.
Monitor
This is the Visual
Display Unit (VDU). There are various technologies for the display unit, cathode
ray tube (CRT) or Liquid Crystal Display (LCD) or the projector. The monitor or
screen displays your work.
2.
Input unit
The input unit is a device which
accepts data and instruction from the user and communicates these to the
central processing unit. The key board in computers is the most common input
unit.
Input device are- Key-board, mouse, scanner,
microphone, photo camera, semi-conductor device for detecting radiations.
Function of input
unit
i.
It
accepts the data and instructions from the user.
ii.
It
converts these data and instruction into the form acceptable to the processing
unit.
iii.
It
transfer the converted data instructions to the central processing unit.
Mouse
This
is the input device used to move a small white arrow pointer-the Cursor on the screen. By pointing and clicking you can carry out
commands.
Key-Board
This is the basic input
device. It is one of the ways you can tell the computer what to do. It consists
of the standard typewriter keys as well as a numeric keypad and function keys. You can use it to give the computer commands.
Peripheral
device
All the parts we have
reviewed so far are usually required for the computer to function. Some other
parts, not required, can also be connected to the computer to complement it. A
peripheral is an object attached to the computer to help it perform some necessary
assignments none of the other parts can handle.
The most
used peripherals are the printer, a digital camera, a scanner, a projector, an
external drive (such as an external CD burner for an old computer), etc.
3.
C.P.U. (Central processing unit)
It is a main part of a computer.
It performs and controls all the operations according to the data and
instructions received from the user by input device.
It
is divided in to three main parts.
·
Control unit
·
Arithmetic and logic unit
·
Memory unit
·
Control
unit
This unit fetches the instruction
from the main store, decodes them and produces signals that carry out the
instructions.
Function of Control
unit
i.
It
is the nerve center of the CPU.
ii.
It
acts as a supervisor.
iii.
It
sends the input from input device to the memory unit.
iv.
If
the input is to be processed, it is sent to the ALU.
v.
It
sends the final results from the memory unit to the output.
·
Arithmetic
and Logic unit (ALU)
It performs all the arithmetical
operations like addition, subtraction, multiplication, division and other logic
operations like taking decisions based on conditional computation.
Function of ALU
Appropriate
operations (addition, subtraction, multiplication, division, comparison of
greater, lesser, equal, positive, negative, zero) are also performed here.
·
Memory
unit
This
unit store the data(like as input data, programs, intermediate results and
final results ready for output).
Function of Memory
unit
i.
The
input, data and instruction, fed in by the user is received and stored in this
unit.
ii.
The
data and program instructions are stored as long as required by the user.
iii.
The
intermediate or final results values processed by the ALU are also stored in
the memory unit.
iv.
The
data, if it has to be processed, is sent to the ALU or the output device from
the memory unit.
Type of Computer
According to the
operating principle, computers are classified in to three types:
1-
Analog
Computer
Analog
computer works on the principle of current and voltage-signal.
Analog
computer can perform the job of measurement and comparison of physical
quantities like velocity, acceleration, force, power, rate of flow, voltage,
light intensity etc.
Analog
computer are widely used in scientific and technological jobs.
2-
Digital
Computer
Digital computer can perform only
calculations. The mathematical data is represented in the form of only two
digit 0 or 1 called binary number. Digital computer are widely used in commercial
jobs.
3-
Hybrid Computer
Hybrid computer is a mixture of
analog and digital computer. Some function are performed in analog part and
some function are done by the digital part. Most modern computers
Operating System
An operating system is a
program that acts as an intermediary between the application programs and the computer
hardware. You cannot directly use computer applications (or programs) with computer hardware without a translation system between
the hardware and the applications. This translation system is called the operating
system (OS).
Computer
Language
The
function of a computer is controlled by set of instructions called a computer
program.
Just
as a common language is needed for communication between two human beings, a
language is needed for communication between the computer and its user. Computer language is the means of
communication between the users and computers.
Type of Computer Language
There
are two types of computer language:
1-
Low
level language
Low
level language is also divided into two type
i.
Machine level language
The binary coded
instructions which the computer can follow is knows as the machine-code and the
sequence in which they are written is called machine level language.
ii.
Assembly level language
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