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Generalized Lock Manager with Arbitrary Intent Specification

IP.com Disclosure Number: IPCOM000052290D
Original Publication Date: 1981-May-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Goldstein, BC: AUTHOR

Abstract

The creator of a lock can define the semantics or rules of lock acquisi Since the mechanism to be described uses purely boolean variables and expressions, the following algorithm could easily be implemented in hardware. Definition and Assumptions

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Generalized Lock Manager with Arbitrary Intent Specification

The creator of a lock can define the semantics or rules of lock acquisi Since the mechanism to be described uses purely boolean variables and expressions, the following algorithm could easily be implemented in hardware. Definition and Assumptions

For a lock there is associated an Access Control Matrix (ACM) which the creator of the lock defines. An ACM is an N x N boolean array where: ACM [I;J]=1=> that a process requesting the lock in state J is willing to share the lock with a process holding the lock in state I. ACM[I;J]=Phi implies that a process requesting the lock in state J is not willing to share the lock with a process holding the lock in state I. If Lambda/ACM [I;]=Phi, then this implies the exclusive state. Only one process requesting a lock in this state can hold the lock. It can also be shown that ACM must be symmetric.

Then, given the current hold state, STATE, of a lock, with ACM, called ACM, and a request, R, the lock algorithm is as follows: See Original

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