Information and Communication Technology

2.1.40 Media Input Devices

Media input devices are used to record information (text an d data) directly on magnetic media. An operator can key the information electronically using a keyboard. The information is displaced on a screen for correcting any errors and then transferred to the magnetic medium. The medium is physically transferred to the computer system for further processing and producing outputs on paper. When changes are required, the medium is returned to the input device for editing. These devices are not electrically connected to the computer and are therefore referred to as off -line data entry systems. The cost of data entry terminals is much less compared to a computer system. If we use off-line data entry systems, we can avoid the use of the computer system for entering data, thus saving CPU time.

Depending on the configuration of the main system, one or more of the following off-line data entry systems may be used:

1. Key-to-floppy
2. Key-to-cassette
3. Key-to-tape

Among these three, the most popular data entry system used in offices is the key-to-flopp y system. Most data entry systems include facilities for defining, storing, verifying and validating large volumes of data. The validation may include type verification on fields, check digit incorporation and hash totalling.

MULTIMEDIA

Multimedia is a c omputer-based method of presenting information by using more than one medium of communication, such as text, graphics, and sound and emphasising interactivity.

Multimedia is changing the way we store, retrieve and read the information. Instead of linear p resentation of text (as printed in books), multimedia makes reading dynamic by the ability to branch to any place in the text and by giving life to it with sound, pictures, music and video. Multimedia is extensively used in teaching, learning and electroni c publishing.