Varying wait interval retry apparatus and method for preventing bus lockout
US5293621A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 11, 1993 |
| Grant date | Mar 8, 1994 |
| Priority date | — |
| Expiry date | Jan 11, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F13/1689
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A User bus lockout prevention mechanism for use in a time-shared bus, multiple bus User, computer architecture where bus Users have private cache systems which perform a cache cycle when a WRITE TO MEMORY instruction occurs on the bus to determine if data cached from main memory has been overwritten in main memory. A User can be locked out from use of the bus if a synchronism occurs between repetitive cache cycles and periodicity of the request Retry mechanism of the User. Bus lockout is prevented by controlling the Retry mechanism of the User to retry requests in accordance with a sequence of varying retry wait intervals. The sequence comprises bursts of short wait intervals interleaved with long wait intervals, the sequence beginning with a burst of short wait intervals. The wait interval durations of the first and second occurring bursts are interleaved with respect to each other. The second occurring long wait is longer than the first occurring long wait. The sequence is terminated upon bus grant.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.