Show your love! Share this page!
A unit of computer system that brings data and instruction into the computer is input unit. It accepts data or instruction given by user and converts into machine readable code if required. Keyboard and mouse are the most popular input unit devices. Other devices of this unit are: light pen, joystick, trackball, microphone, scanners, sensors, graphic tablet, touch screen etc.
The term input is used to describe the process of capturing or collecting raw data, at the beginning of computer based information system, into a form that is usable by the computer for processing. Sometimes the data is processed right away(online processing), sometimes hours or days later or even longer (batch processing), as a result the data is often stored in a computer usable form, where it can be quickly retrieved at the time of processing with little or no longer intervention.
Input unit devices can be classified into two groups based on whether the data conversion is involved or not – direct input devices and indirect input devices:
In this input method, data is already in machine readable form and thus, no need to convert it. The data is directly feed into computer to process. Some examples of direct input devices are Point of Sales Terminals (POS), Credit Cards, and Scanners etc. Credit card contains a magnetic strip that contains data in machine readable form and when you insert the card into ATM machine, it can directly feed data for processing.
If the data is in human readable form, it must be converted into machine readable form so that a computer can process it. This process of data conversion is time consuming and error prone that causes a major bottleneck in data processing. Some examples of indirect input devices are: keyboard, mouse and joystick. When you press any key on keyboard, it converts that character into series of electronic pulses and sends to CPU.