1. Field of the Invention
This invention relates to a medium sized peripheral processing system which provides sophisticated interactive communication with human operators and more particularly to a data entry system providing centralized programmable control of data entry stations on a character-by-character basis.
2. Description of the Prior Art
Rapid advances have been made in the development of data entry systems. For many years the keypunch machine was the most popular device for converting data into machine readable form. A keypunch receives a small, multi-column card and punches a hole pattern in one column of the card for each activation of a data key. A typical card contains 80 columns for the storage of 80 characters in what has become known as a block of data. Card readers are able to sense the pattern of holes punched in a card for automatic conversion to an electrical or magnetic code for use by other data processing equipment. While cards can be read much faster than an operator can punch them, the operation is quasi-mechanical in nature and extremely slow in comparison to present day data processing speeds. The keypunch also has the disadvantage of requiring a bulky, expensive, nonreusable card for each block of information.
Some of these disadvantages were overcome by the key-to-tape systems which have become popular. These systems permit keyed information to be transferred directly to magnetic tape with no requirement for intermediate use of punched cards. Typically, a block of keyed information is accumulated in electrically alterable memory at a key station and then transferred as a block to either a local magnetic tape file or a central tape file which pools blocks of information from several key stations. A completed tape may then be transferred to a tape file of a large capacity main frame data processing system for rapid input and processing of the information. Some centralized control and programming of the key stations is possible in most systems, but the key-to-tape key stations are primarily self-sufficient units with each having its own controls, buffer memories and other equipment.
More recently, key-to-disc systems have been developed which permit increased centralized programming for many key stations. Keyed data is stored at a central disk file instead of at separate magnetic tape files for each key station and a large central memory permits more sophisticated control over information format programming and system personnel. However, such systems have heretofore failed to realize the full advantages which are afforded by such a system.