COMPUTER COMPONENTS
Basic computer organization
All types of computers follow a same
basic logical structure and perform the following five basic operations for
converting raw input data into information useful to their users
1. Input Unit
This unit contains devices with the
help of which we enter data into computer. This unit makes link between user
and computer.
The input devices translate the human
being information into the form understandable by computer.
2. CPU (Central Processing
Unit)
CPU is considered as the brain of the
computer. CPU performs all types of data processing operations. It stores data,
intermediate results and instructions (program). It controls the operations of
all parts of computer.
CPU itself has the following three components
(1) ALU (Arithmetic Logic Unit)
(2) Memory Unit
(3) Control Unit
3. Output Unit
Output unit consists of devices with
the help of which we get the information from computer. This unit is a link
between computer and users.
Output devices translate the
computer's output into the form understandable by users.
COMPUTER – CPU
CPU (Central
Processing Unit)
·
CPU is considered as the brain of the computer.
·
CPU performs all types of data processing operations.
·
It stores data, intermediate result and instructions (program).
·
It controls the operations of all parts of computer.
CPU itself has the
following three components.
·
Memory or Storage Unit:
·
Control Unit
·
ALU (Arithmetic Logic Unit)
Memory or Storage Unit:
This unit
can store instructions, data and intermediate results. This unit supplies
information to the other units of the computer when needed. It is also known as
internal storage unit or main memory or primary storage or Random access memory
(RAM).
Its size
affects speed, power and capability. There are primary memory and secondary
memory, two types of memories in the computer. Functions of Memory Unit are:
(1) It
stores all the data to be processed and the instructions required for
processing.
(2) It
stores intermediate results of processing.
(3) It
stores final results of processing before these results are released to an
output device.
(4) All
inputs and outputs are transmitted through main memory.
Control Unit
This unit
controls the operations of all parts of computer. It does not carry out any
actual data processing operations.
Functions of this unit are:
CIt
is responsible for controlling the transfer of data and instructions among other
units of a computer.
C It manages
and coordinates all the units of the computer.
C It
obtains the instructions from the memory, interprets them and directs the
operation of the computer.
C It
communicates with Input/output devices for transfer of data or results from
storage.
C It
does not process or store data.
ALU (Arithmetic Logic Unit)
This unit
consists of two subsections namely:
(A) Arithmetic
Section
(B) Logic
Section
(1)Function of Arithmetic
section is to perform arithmetic operations like
addition, subtraction, multiplication and division. All complex operations are
done by making repetitive use of above operations.
Logic Section
Function of
logic section is to perform logic operations such as comparing, selecting,
matching and merging of data.
INPUT DEVICES
Following are
few of the important input devices, which are used in Computer Systems:
C Keyboard
C Mouse
C Joystick
C Light pen
C Track Ball
C Scanner
C Graphic
Tablet
C Microphone
C Magnetic Ink
Card Reader (MICR)
C Optical
Character Reader (OCR)
C Bar Code
Reader
C Optical Mark
Reader
Keyboard
Most common
and very popular input device is keyboard. The keyboard helps in inputting the
data to the computer. The layout of the keyboard is like that of traditional
typewriter, although there are some additional keys provided for performing
some additional functions.
Keyboards are of two sizes 84 keys or
101/102 keys, but now 104 keys or 108 keys keyboard is also available for
Windows and Internet.
The keys are following
|
Sr. No.
|
Keys
|
Description
|
|
1
|
Typing Keys
|
These keys include the letter keys (A-Z) and digits
keys (0-9) which generally give same layout as that of typewriters.
|
|
2
|
Numeric Keypad
|
It is used to enter numeric
data or cursor movement. Generally, it consists of a set of 17 keys that are
laid out in the same configuration used by most adding machine and
calculators.
|
|
3
|
Function Keys
|
The twelve functions keys
are present on the keyboard. These are arranged in a row along the top of the
keyboard. Each function key has unique meaning and is used for some specific
purpose.
|
|
4
|
Control keys
|
These keys provide cursor and screen control. It
includes four directional arrow key. Control keys also include Home, End,
Insert, Delete, Page Up, Page Down, Control(Ctrl), Alternate(Alt),
Escape(Esc).
|
|
5
|
Special Purpose Keys
|
Keyboard also contains some special purpose keys such
as Enter, Shift, Caps Lock, Num Lock, Space bar, Tab, and Print Screen.
|
