Inventor: Robert H Nagel

US patent number:4,064,490

US patent application date: September 10, 1975
US patent issue date: December 20, 1977

SYNOPSIS OF THE INVENTION

This system provides an information retrieval system which comprises a remote information source for remotely transmitting information in a predetermined format over a common predetermined transmission media.

The system also provides a local selectable purpose variable function terminal operatively connected to the remote information source via the common transmission media for selectively receiving the remotely transmitted information.

The remotely transmitted information comprises displayable data, such as video displayable data or data displayable on any other type of display means, such as a printer, and a plurality of different sets of control instructions for the terminal. Each of the sets of control instructions corresponds to a different selectable purpose for the terminal.

Selection means, such as a keyboard means, are operatively connected to the microcomputer means for variably selecting a first selectable purpose for the terminal from a plurality of different selectable purposes for the terminal, the selectable purposes being variable.

Local storage means, such as a random access memory means, are provided for selectively retrievably locally storing either the remotely transmitted displayable data or a first one of the remotely transmitted selected set of control instructions for the microcomputer means corresponding to the first selected purpose for the terminal. The local storage means is operatively connected to the microcomputer means.

Means for selectively controlling the local storage of the remotely transmitted information in the local storage means dependent on the selected purpose of the terminal are also provided with such local storage control means being operatively connectable to the microcomputer means to the selection means, and to the local storage means.

The microcomputer means is operable in accordance with the locally stored remotely transmitted first one of a selected set of control instructions. Display means, such as a video display terminal or some other type of display device for data, such as a printer, is operatively connected to the microcomputer means.

To select a program, the user depresses a program number on a keyboard followed by the program key. This information is provided to the local microcomputer which sets up the correct search address bits. In normal fashion, the terminal raises an address compare line when a match is found to the incoming data. The permanently stored loader and executive program for the microcomputer is permanently stored in the read only memory or ROM, which, by controlling the microcomputer, stores the incoming information in the random access memory or RAM as instruction sets to be executed, rather than as data, for the program selected.

When the entire requested program has been loaded, the microcomputer turns control from the loader program to the newly entered called program which operates the terminal in accordance with the selected purpose. When it is desired to select a different program, the appropriate keys are again depressed and control is again returned to the loader and executive program which operates as previously described to load the newly requested program into the random access memory and then turn control of the microcomputer over to it.

The information retrieval system for providing the down stream program grabbing or loading could be implemented either in a two way communication system or in a one way communication system, such as one employing row grabbing where the sets of instructions or programs as well as data are continuously transmitted from the remote data source.