Function keys across the top
Letter keys in the main section
A numeric keypad on the right
Cursor movement and editing keys between the main section and the numeric keypad.
The layout of the letters on a keyboard is standard across many countries and is called a QWERTY keyboard. The name comes from the first …show more content…
When a key is pressed, a digital code is sent to the Central Processing Unit (CPU). This digital code is translated into ASCII code (American Standard Code of Information Interchange).
For example, pressing the 'A' key produces the binary code 01100001 representing the lower case letter 'a'. Holding down the shift key at the same time produces the binary code 01000001 representing the upper case letter 'A'.
Advantages:
Most computers have this device attached to it
It is a reliable method for data input of text and numbers
A skilled typist can enter data very quickly.
Specialist keyboards are available
Disadvantages:
It is very easy to make mistakes when typing data in
It can be very time consuming to enter data using a keyboard, especially if you are not a skilled typist.
It is very difficult to enter some data, for example, details of diagrams and pictures.
It is very slow to access menus and not flexible when you want to move objects around the screen
Difficult for people unable to use keyboards through paralysis …show more content…
Buttons on the mouse let you select options from menus and drag objects around the screen. Pressing a mouse button produces a 'mouse click'. You might have heard the expressions 'double click', 'click and drag' and 'drag and drop'.
Most mice use a small ball located underneath them to calculate the direction that you are moving the mouse in. The movement of the ball causes two rollers to rotate inside the mouse; one records the movement in a north-south direction and the other records the east-west movement. The mouse monitors how far the ball turns and in what direction and sends this information to the computer to move the pointer.
Advantages: Ideal for use with desktop computers.
Usually supplied with a computer so no additional cost.
All computer users tend to be familiar with using them.
Disadvantages
They need a flat space close to the computer.
The mouse cannot easily be used with laptop, notebook or palmtop computers. (These need a tracker ball or a touch sensitive pad called a touch pad).