Two level store with many-to-one mapping scheme
AssigneeInternational Computers Limited
InventorsPeter L. Desyllas, Barry G. Radley, Alasdair Rawsthorne, John R. Eaton, John E. Murray
Life of this patent
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Abstract
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.
Claims4
In a data processing system having a main store connected to a smaller, faster slave store into which data items are copied from the main store on demand, the data items in the main store being mapped on to the locations of the slave store according to a many-to-one mapping scheme, the improvement comprising:
- (a) a further store connected in tandem with the slave store, the further store being of smaller size than the slave store and having an access speed comparable to that of the slave store;
- (b) means connected to the slave store for producing a control signal when an attempt is made to access from the slave store two different data items which map on to the same location of the slave store, and
- (c) means connected to the slave store and further store, and responsive to said control signal, for suspending addressing of the slave store and addressing the further store instead when the control signal is present.
Dependencies are inferred from the claim text.