System for arbitrating use of I/O bus by co-processor and higher

Details System for arbitrating use of I/O bus by co-processor and higher System for arbitrating use of I/O bus by co-processor and higher

1985-02-28

1987-10-27

Harkcom, Gary V.

Boots, shoes, and leggings

G06F 1318

Patent

active

047034203

ABSTRACT:
A data processing system having a main processing unit, a memory subsystem, and a co-processor selectively connectable to said memory subsystem through an Input/Output Channel Controller which includes a control means for arbitrating access to the I/O Bus among the co-processor and the other I/O devices connected to the Bus. Since the co-processor runs programs stored in the memory subsystem, there is a tendency for the co-processor to monopolize the bus with instruction fetch cycles, thereby excluding other I/O devices from access to the bus. The control means for arbitrating responds to requests on the basis of a linear priority scheme in which the co-processor has the lowest priority. Each device, except the co-processor, is permitted to keep control of the bus until it voluntarily relinquishes it. The co-processor, on the other hand, relinquishes control of the bus in response to a request for access by any higher operator. However, control is returned automatically to the co-processor in the absence of any other request, since the co-processor continually raises its access request line.

REFERENCES:
patent: 4403303 (1983-09-01), Howes
patent: 4417304 (1983-11-01), Dinwiddie
patent: 4441162 (1984-04-01), Lillie
patent: 4453214 (1984-06-01), Adcock
patent: 4463445 (1984-07-01), Grimes
patent: 4493036 (1985-01-01), Boupreau et al.
patent: 4556952 (1985-12-01), Brewer
patent: 4562535 (1985-12-01), Vincent
patent: 4602327 (1986-07-01), LaViolette
"Memory Access Technique", by H. T. Ward, IBM Technical Disclosure Bulletin, vol. 21, No. 3, pp. 992-994.
IBM Tech. Disclosure Bull., vol. 26, No. 7A, Dec. 1983, "Method for Decreasing Arbitration Overhead", by Bergey et al, pp. 3370-3371.

Affiliated with

Also associated with

Rating

System for arbitrating use of I/O bus by co-processor and higher does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with System for arbitrating use of I/O bus by co-processor and higher, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System for arbitrating use of I/O bus by co-processor and higher will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1275709