MBA
SUBJECT NAME: Computer
Applications and Management Information System
Subject Code: RMB 108
UNIT 1(conceptual frame
work)
Hardware:
(a) Input Devices
Following are some of the important input devices which are used
in a computer −
- Keyboard
- Mouse
- Joy Stick
- Light pen
- Track Ball
- Scanner
- Graphic Tablet
- Microphone
- Magnetic Ink Card Reader(MICR)
- Optical Character Reader(OCR)
- Bar Code Reader
- Optical Mark Reader(OMR)
Keyboard
Keyboard
is the most common and very popular input device which helps to input data to
the computer. The layout of the keyboard is like that of traditional
typewriter, although there are some additional keys provided for performing
additional functions.
Keyboards
are of two sizes 84 keys or 101/102 keys, but now keyboards with 104 keys or
108 keys are also available for Windows and Internet.
The keys
on the keyboard are as follows −
S.No
|
Keys & Description
|
1
|
Typing Keys
These keys include the
letter keys (A-Z) and digit keys (09) which generally give the same layout as
that of typewriters.
|
2
|
Numeric Keypad
It is used to enter the
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 machines and
calculators.
|
3
|
Function Keys
The twelve function keys
are present on the keyboard which are arranged in a row at the top of the
keyboard. Each function key has a unique meaning and is used for some
specific purpose.
|
4
|
Control keys
These keys provide cursor
and screen control. It includes four directional arrow keys. 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.
|
Mouse
Mouse is
the most popular pointing device. It is a very famous cursor-control device
having a small palm size box with a round ball at its base, which senses the
movement of the mouse and sends corresponding signals to the CPU when the mouse
buttons are pressed.
Generally,
it has two buttons called the left and the right button and a wheel is present
between the buttons. A mouse can be used to control the position of the cursor
on the screen, but it cannot be used to enter text into the computer.
Advantages
- Easy to use
- Not very expensive
- Moves the cursor faster than the
arrow keys of the keyboard.
Joystick
Joystick
is also a pointing device, which is used to move the cursor position on a
monitor screen. It is a stick having a spherical ball at its both lower and
upper ends. The lower spherical ball moves in a socket. The joystick can be
moved in all four directions.
The
function of the joystick is similar to that of a mouse. It is mainly used in
Computer Aided Designing (CAD) and playing computer games.
Light Pen
Light pen
is a pointing device similar to a pen. It is used to select a displayed menu
item or draw pictures on the monitor screen. It consists of a photocell and an
optical system placed in a small tube.
When the
tip of a light pen is moved over the monitor screen and the pen button is
pressed, its photocell sensing element detects the screen location and sends
the corresponding signal to the CPU.
Track Ball
Track
ball is an input device that is mostly used in notebook or laptop computer,
instead of a mouse. This is a ball which is half inserted and by moving fingers
on the ball, the pointer can be moved.
Since the
whole device is not moved, a track ball requires less space than a mouse. A
track ball comes in various shapes like a ball, a button, or a square.
Scanner
Scanner
is an input device, which works more like a photocopy machine. It is used when
some information is available on paper and it is to be transferred to the hard
disk of the computer for further manipulation.
Scanner
captures images from the source which are then converted into a digital form
that can be stored on the disk. These images can be edited before they are
printed.
Digitizer
Digitizer
is an input device which converts analog information into digital form.
Digitizer can convert a signal from the television or camera into a series of
numbers that could be stored in a computer. They can be used by the computer to
create a picture of whatever the camera had been pointed at.
Digitizer
is also known as Tablet or Graphics Tablet as it converts graphics and
pictorial data into binary inputs. A graphic tablet as digitizer is used for
fine works of drawing and image manipulation applications.
Microphone
Microphone
is an input device to input sound that is then stored in a digital form.
The
microphone is used for various applications such as adding sound to a
multimedia presentation or for mixing music.
Magnetic Ink Card Reader (MICR)
MICR
input device is generally used in banks as there are large number of cheques to
be processed every day. The bank's code number and cheque number are printed on
the cheques with a special type of ink that contains particles of magnetic
material that are machine readable.
This
reading process is called Magnetic Ink Character Recognition (MICR). The main
advantages of MICR is that it is fast and less error prone.
Optical Character Reader (OCR)
OCR is an
input device used to read a printed text.
OCR scans
the text optically, character by character, converts them into a machine
readable code, and stores the text on the system memory.
Bar Code Readers
Bar Code
Reader is a device used for reading bar coded data (data in the form of light
and dark lines). Bar coded data is generally used in labelling goods, numbering
the books, etc. It may be a handheld scanner or may be embedded in a stationary
scanner.
Bar Code
Reader scans a bar code image, converts it into an alphanumeric value, which is
then fed to the computer that the bar code reader is connected to.
Optical Mark Reader (OMR)
OMR is a
special type of optical scanner used to recognize the type of mark made by pen
or pencil. It is used where one out of a few alternatives is to be selected and
marked.
It is specially used for checking the answer sheets of examinations having multiple choice questions.
