Cache coherency protocol for multi processor computer system
US5297269A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 24, 1993 |
| Grant date | Mar 22, 1994 |
| Priority date | — |
| Expiry date | May 24, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F12/0828
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A cache coherency protocol for a multi-processor system which provides for read/write, read-only and transitional data states and for an indication of these states to be stored in a memory directory in main memory. The transitional data state occurs when a processor requests from main memory a data block in another processor's cache and the request is pending completion. All subsequent read requests for the data block during the pendency of the first request are inhibited until completion of the first request. Also provided in the memory directory for each data block is a field for identifying the processor which owns the data block in question. Data block ownership information is used to determine where requested owned data is located.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.