Computer Fundamentals

1. Input Devices
Input devices allow users and other applications to input data into the computer, for
processing. The data input to a computer can be in the form of text, audio, video,
etc.
Computer input devices are an essential part of any computer system. Without an
input device, we will not be able to interact with a computer. Most of us are familiar
with the keyboard and mouse as input devices, but we may be surprised at the wide
variety of other devices that are currently available for inputting data into a
computer.
Following are some of the important input devices which are used in a computer −
 Keyboard
 Mouse
 Joy Stick
 Light pen
 Track Ball
 Scanner
 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.
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.

2. The keys on the keyboard are as follows:
SL.
No.
Keys & Description
1
Typing Keys
These keys include the letter keys (A-Z) and digit keys (09).
2
Numeric Keypad
It is used to enter the numeric data or cursor movement. Generally, it
consists of a set of 17 keys.
3
Function Keys
The twelve function keys (F1-F12) are present on the keyboard which
are arranged in a row at the top of the keyboard.
4
Control 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.
How keyboard works?

3. Mouse
A computer mouse is a handheld hardware input device that controls a cursor in
a GUI and can move and select text, icons, files, and folders.
What are the uses of a mouse?
1. Move the mouse cursor - The primary function is to move the mouse
pointer on the screen.
2. Open or execute a program - Once we've moved the pointer to an icon,
folder, or other object clicking or double clicking that object opens
the document or executes the program.
3. Select - A mouse also allows us to select text or a file
or highlight and select multiple files at once.
4. Drag-and-drop - Once something is selected it can also be moved using
the drag-and-drop method.
5. Hover - Moving the mouse cursor over objects with
additional hover information can help discover the function of each object
on the screen.
6. Scroll - When working with a long document or viewing a long web
page you may need to scroll up or down which can be done using
the mouse wheel or clicking and dragging the scroll bar.
Advantages
 Easy to use
 Not very expensive
 Moves the cursor faster than the arrow keys of the keyboard.
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.

4. Advantages of Track Ball
 The advantage of trackballs over mice is that the trackball is stationary so it
does not require much space to use it.
 We can place a trackball on any type of surface, including our lap.
 A trackball mouse has ergonomic advantages because we move the ball and
not the mouse itself.
 The buttons are well placed and it helps in reaching the finger in a proper way.
Disadvantages of Track Ball
 Left-handed trackballs are difficult to find.
 Trackballs are expensive.
 A trackball requires fine control of the ball with just one finger or thumb.
 Difficult to Use.
Why Trackball useless Nowadays?
 A trackball is usually not as accurate as a mouse.
 The trackball is in a strange place these days
 Nowadays a lot of amazing features in Windows are available and new
technology exists a lot.
 There are many reasons for example:
 Left-handed trackballs are difficult to find.
 Trackballs are expensive.
Light Pen
A light pen may refer to the following:
 A light pen is a light-sensitive pointing input device commonly used to select
or otherwise modify text or data on a screen.

5. Joystick
A joystick is an input device that allows the user to control a character or machine
in a computer program, such as a plane in a flight simulator.
Advantages of joysticks Disadvantages of joysticks
They give a better gaming
experience for racing or flying
styles of computer games
Some people find joysticks more
difficult to control than a traditional
mouse.
Joysticks are not particularly robust
and can break easily if too much force
is used on them.
Touch Screen
A touchscreen is a display device that allows the user to interact with a computer by
using their finger. They can be quite useful as an alternative to a mouse or keyboard
for navigating a graphical user interface (GUI). Touchscreens are used on a variety
of devices such as computer and laptop monitors, smartphones, tablets etc.

6. How do you use the touchscreen?
 Tap: A single touch or tap on the screen with a finger opens an app or select
an object. When compared to a traditional computer, a tap is the same
as clicking with a mouse.
 Double-tap: A double-tap can have different functions depending on where
it is utilized. For example, in a browser, double-tapping the screen zooms in
at the tap location. Double-tapping in a text editor can be used to select a word
or section of words.
 Touch and hold: Pressing and holding your finger to a touchscreen selects
or highlights an object. For example, we could touch and hold an icon, and
then drag it somewhere else on the screen.
 Swipe: Swiping our finger across the screen can be used to scroll in a certain
direction or change pages. For example, pressing our finger at the bottom of
the screen and quickly moving it up (swiping) scrolls the screen down.
 Pinch: Placing two fingers on the screen in different spots and then pinching
them together zooms out. Pinching our fingers together and then moving them
away from each other, zooms in on the screen.
OMR
Short for Optical Mark Reading or Optical Mark Recognition, OMR is the process
of gathering information from human beings by recognizing marks on a document.
OMR is accomplished by using a hardware device (scanner) that detects a reflection
or limited light transmittance on or through a piece of paper.

7. Why is OMR an input device?
The OMR card by itself is not considered an input device. However, the OMR reader
that reads the card is sending data (input) to the computer, which is why it is
considered an input device.
OCR
An OCR system consists of a normal scanner and some special software. The
scanner is used to scan text on a document or piece of paper into the computer. The
OCR software then examines the page and changes the letters into a form that can
be edited or processed by a normal word processing package. The ability to scan the
characters accurately depends on how clear the writing is.

8. Advantages of OCR Disadvantages of OCR
Cheaper than paying
someone to manually enter
large amounts of text
Not 100% accurate, there are likely to be
some mistakes made during the process
Much faster than someone
manually entering large
amounts of text
All documents need to be checked over
carefully and then manually corrected
The latest software can
recreate tables and the
original layout
If the original document is of poor quality
or the handwriting difficult to read, more
mistakes will occur
Scanner
A scanner may refer to any of the following:
When referring to hardware, a scanner or optical scanner is a hardware input
device that optically "reads" an image and converts it into a digital signal. For
example, a scanner may be used to convert a printed picture, drawing, or document
(hard copy) into a digital file which can be edited on a computer. The picture shows
an example of a flatbed scanner, the EpsonV300.

9. Other types of computer scanners
There are also other types of scanners that can be used with a computer.
 Sheetfed scanner - scans paper by feeding it into the scanner
 Handheld scanner - scans text and images by dragging the device over the
page you want to scan
 Card scanner - designed to scan business cards
Why is a scanner an input device?
A computer scanner is an input device because it takes information from the real
world (e.g., a document or picture) and converts it into digital information for a
computer to store or manipulate. A scanner is only able to send information to the
computer and cannot receive information from the computer like a printer (which is
an output device).