International Business Machines Corporation

John Simmons

David John Roberts

Brian H Middleton

Paul H Benson

Martin C Pinnell

Thomas E Robinson

Michael L Kingdom-Hockings

Richard E Sheeler

Described is an interactive enquiry system in which a complete data base is contained at a host computer. Local terminal sub-systems are remotely connected to the host with each local sub-system containing a local data base. Each local data base is dynamically maintained so that the most frequently used pages are retained in local storage. If storage space needs to be created, the least frequently used pages are discarded from the local data base.

Interactive enquiry system

A data processing system is described which issues value documents e.g. tickets or information under the control of output instructions and is designed to prevent a person attempting fraud using an unauthorized program obtaining the value documents or information. The system includes a data processor controlling output units which can issue value documents or information and data storage. The data storage is divided into a secure store containing the output instructions arranged to make tampering difficult and a free storage into which an operator may load a program. Security logic is provided to check that an output instruction has originated in the secure store and to prevent operation of an output unit which receives output instructions from free storage. This makes it difficult for a person attempting fraud to produce value documents or information by loading a program into free storage. The secure storage is preferably a read only store programmed during manufacture. When secure and free storage share a common memory bus, the security logic monitors addresses used to fetch instructions.

Protection of data processing system against unauthorized programs

Growing community of inventors

Chandlers Ford, United Kingdom

John Simmons