Input

 

Communicating with computers has always been a problem. In the early days, programrs had to communicate directly to the computer in its own language. Main, rather than the machine has to do the translating. The difficulties of having to think in binary led man to develop easier methods of communication. In some cases he was able to do this by making use of existing technology from other fields. For example, the use of punched cards and perforated tape by people unfamiliar with binary permitted the encoding of our familiar symbols into an intermediate stage. This intermediate stage is then translated into binary by the machine.

 

Since the early days, developments have taken place which permit the computer to 'read' our typed (and even written) symbols directly via mark recognition (mark reading, mark sensing), magnetic ink character recognition (MICRO) and optical character recognition (OCR). There have also developments which have led to typewriter input (teletypewriter) devices and to visual (TV - type) display devices equipped with keyboards for input. More recently, hand-held terminal entry systems and hand-print pads have been introduced, and research into voice input has been successful enough for some commercial companies to use this method of communication in a limited way. The most widely used input devices today are teletypewriter terminals and visual display devices, which also double as output devices.