The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 23, 1994
Filed:
Oct. 22, 1993
Raj Ramanujan, Leominster, MA (US);
Digital Equipment Corporation, Maynard, MA (US);
Abstract
A lockout avoidance circuit is provided for a plurality of nodes which generate lock requests for a shared resource such as a memory location. The circuit insures that lock requests are eventually satisfied. A lock queue includes a plurality of registers pipelined together. Lock requests only enter the lock queue if they are refused access to a shared resource a predetermined number of times. A first register is the head of the queue and the last register is the bottom of the queue. An enabling circuit allows the queue to store in the registers lock requests received from the different nodes in the order in which they are initially refused service. The enabling circuit operates the queue by pushing the stored lock requests toward the head of the queue each time the head entry in the queue is serviced. The lockout avoidance circuit is implemented at each level of the system wherein a lockout condition can occur.