2. For better utilization, a computer system needs to communicate with its
external environment ( its user ).Input & Output devices ( I/O devices )
provides this capability to a system. They are also known as Peripheral
devices. Input devices enter data from outside world into primary storage
and output devices supply the results of processing from primary storage to
users.
I/O devices are directly connected to an electronic module called I/O
module or device controller. For example, the speakers of a multimedia
computer system are directly connected to a device controller called an
audio card, which in turn is connected to the rest of the system.
INTRODUCTION
4. INPUT DEVICES
An input device is an electro-mechanical device that
accepts data from outside world and translate them into
an understandable language which a system can interpret.
Input devices are hardware devices that allows data to be
input into a computer system manually or automatically.
e.g. Keyboard, Mouse, Touchpad, Joystick, Scanner,
Microphone, etc.
6. Keyboard Devices
Most commonly used input device used to enter data and information into
the computer system.
Keyboards allow a computer user to input letters, numbers, and other
symbols into a computer.
Uses an arrangement of keys.
All the keys are neatly mounted in a keyboard connected to the computer
system.
Keyboard devices can be classified into two types general purpose keyboards
and special purpose keyboards.
7. o Function Keys: These keys are assigned a special task or function.( F1 to
F12 )
o Typewriter Keys: Letters, numbers, and punctuation keys. Additional
keys include the space bar, shift key and Caps Lock key for a series of
capital letters.
o Cursor Control Keys: Also called arrow keys or Hot Keys, which move
your text cursor in the direction of the arrow. ( )
o Numeric Keypad: Similar to a calculator for entering numbers & doing
mathematical operations quickly and easily. ( 0 to 9 )
o Locking Keys: These keys change how certain parts of the keyboard
respond.( Caps lock, Num lock, Scroll lock )
o Navigation keys: Arrow keys, Page Up/Page Down, Home, and End are
convenient to move your cursor to the desired location.
8. Types of Keyboard
I. Standard Keyboard
Desktop computer keyboards,
such as the 101-key US
traditional keyboards or the 104-
key Windows keyboards, include
alphabetic characters,
punctuation symbols, numbers
and a variety of function keys.
II. Laptop Keyboard
The laptop computer keyboard is
a small version of the typical
QWERTY keyboard.
A typical laptop has the same
keyboard type as a normal
keyboard, except for the fact that
most laptop keyboards condense
the symbols into fewer buttons to
accommodate less space.
9. III. Gaming & Multimedia
keyboard
The gaming keyboards are designed for
the convenience of the gamers and
these types of keyboards provide the
required controls on the keyboards like
back lighting.
IV. Thumb-sized keyboard
Smaller external keyboards
have been introduced for
devices without a built-in
keyboard, such as PDAs, and
smartphones.
Small keyboards are also
useful where there is a limited
workspace.
10. V. Virtual Keyboard
The virtual keyboards are not actually
physical keyboards, but they are
simulated using a software.
VI. Foldable Keyboard
Foldable keyboards are extremely
convenient, simply roll them up and
then unroll them.
12. Keyboard Shortcut Keys
Minimize window
Maximize window
Restore window
Switch application/window
- File menu options in current program
- Edit options in current program
- Universal Help in almost every Windows
program
- Select all text
- Cut selected item
/ - Copy selected item
/ - Paste selected item
- Print the current page or document
- Goes to end of current line
- Goes to end of document.
- Highlights from current
position to beginning of line
- Highlights from current position
to end of line
- Moves one word to the left
at a time
- Moves one word to the
right at a time
- Goes to beginning of current line.
- Goes to beginning of document
Open Task Manager
Restart / Warm boot
Logout / Log off
Open My Computer
Open Run Command
13. Point and Draw Devices
The introduction of GUI ( Graphical User Interface ) provides a computer screen
with graphic icons or menus and allows a user to make rapid selections from
them to give instructions to a computer. For efficient utilization, GUI requires
an input device with which a user can rapidly select a graphic icon or menu
from multiple options displayed on the screen. Hence, to meet this
requirement gave birth to several input devices like mouse, trackball, joystick,
light pen, touch screen, etc.
They are called point & draw devices these are useful for effectively creating
graphic elements on the screen such as lines, curves, freehand shapes, etc.
14. A Mouse is a handy device which can be moved on a smooth surface to
cause the movement of a cursor on the screen. It is a pointing device which
is used to input data and information into the computer system by pointing
on it. Physically, a mouse contains a small case, held under one of the user’s
hands with one or more buttons. For GUI-based systems a mouse is an
essential pointing-device. The cursor of the mouse moves in the same
direction in which the mouse ball rolls.
Mouse
15. Types of Mouse
Mechanical Mouse : Mechanical Mouse uses ball for the movement of
cursor on the computer screen. When the ball is rolled in any direction, a
sensor of the mouse detects it and also moves the mouse pointer in the same
direction.
Optical Mouse : Optical Mouse uses Laser rays for the movement of cursor
on the computer screen. It is an advanced pointing device. Movement is
detected by sensing changes in the reflected light rather than the motion of a
rolling sphere.
Cord-Less Mouse : Cord-Less Mouse is battery driven and does not need
any wire for the physical connection with the motherboard. It transmits data
through infrared or radio signal.
16. Wired Mouse : A wired mouse connects to a computer with a cord (wire) which
is directly connected to an electronic module of the system.
Serial and Bus Mouse : A serial mouse plugs into a serial port (a built-in-socket
in a computers back panel to which we can connect external devices).It does not
require a special electronic card for connecting the mouse to the computer.
A bus mouse requires a special electronic card which provides a special port for
connecting the mouse to the computer. The special electronic card fits into the
expansion slots of the system and thus occupies one of the expansion slots.
One, two and Three buttons Mouse : A mouse can have one, two or three
buttons. A one button mouse is sufficient enough for such programs that are
designed to use only a single button but some programs operate with a two or
three button mouse.