The following functions are carried out by input devices:
1. They accept data from the outside world.
2. They convert this data into binary form acceptable to the machine.
3. They send data in binary form to the computers for further processing.
A keyboard looks like a typewriter. It enables one to enter data into a computer. Computer keyboards are similar to electronic-typewriter keyboards but contain additional keys. The keys on computer keyboards are often classified as follows:
1. Alphanumeric keys - Letters and numbers
2. Punctuation keys - comma, period, semicolon and so on.
3. Special keys - function keys, control keys, arrow keys, caps lock key, etc.
In normal usage, the keyboard is used to type text and numbers into a word processor, text editor or other program. In a modern computer, the interpretation of key presses is generally left to the software. A computer keyboard distinguishes each physical key from every other and reports all key presses to the controlling software.
Keyboards are also used for computer gaming, either with regular keyboards or by using keyboards with special gaming features, which can expedite frequently used keystroke combinations. A keyboard is also used to give commands to the operating system of a computer, such as Windows' Control-Alt-Delete combination, which brings up a task window or shuts down the machine. It is the only way to enter commands on a command-line interface.