Method and apparatus for managing multiple lock indicators in a multiprocessor computer system
US5068781A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 28, 1989 |
| Grant date | Nov 26, 1991 |
| Priority date | — |
| Expiry date | Jun 28, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F13/4217
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A computer system having multiple processors interconnected by a pended bus provides exclusive read-modify-write operations employing multiple lock bits. A processor generates an interlock read command which is transmitted as a transfer over the pended bus to a memory or I/O node. Acknowledge confirmations are transmitted by the memory back to the processor two bus cycles after each bus cycle of the processor transfer. The processor transfer, including an interlock read command, is stored in a input queue in memory and processes in turn by the memory. A first interlock read command to a specified memory location causes a lock bit to be set for that location and a first type of response message including the contents of the specified location to be generated by the memory and stored in an output queue. The memory obtains access to the pended bus through an arbitration process and transmits a response message including the contents of the memory location specified in the interlock read command at an unspecified time after initiation of the interlock read command. A subsequent interlock read command from the processor to the same memory location will result in a denial of access to th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.