International Computers Limited

Barry Gordon Radley

John Richard Eaton

Peter L Desyllas

Graham Donald Inglis

John E Murray

Alasdair Rawsthorne

A data processing system has at least one processing module containing one or more blocks of memory, having control registers which are accessible via a diagnostic interface, and a clock module which distributes system clocks to the processing module(s), the operation of which is controllable using a similar diagnostic interface. One of the possible actions in the clock module is the generation of a single-shot clock pulse. A diagnostic control unit is connected to the separate diagnostic interfaces of the processing module(s) and the clock module, and is capable of simultaneously controlling the two diagnostic interfaces in such a way that a single-shot clock pulse can be synchronized with the diagnostic access to a processing module to effect the loading or dumping of a block of memory line by line.

Diagnostic memory access

A data processing system has a two-level storage system in which data items are copied from a main store into a smaller, faster slave store on demand. The mapping of the main store on to the slave store is a many-to-one mapping so that situations will occur where two required data items cannot both be present simultaneously in the slave store because they map on to the same location. The system has special logic which detects this situation and, upon detection, temporarily suspends the use of the slave store and instead uses a smaller first-in first-out area of storage.

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Glossop, United Kingdom

Barry Gordon Radley