Accession Number:

ADA061407

Title:

Naming and Synchronization in a Decentralized Computer System.

Descriptive Note:

Doctoral thesis,

Corporate Author:

MASSACHUSETTS INST OF TECH CAMBRIDGE LAB FOR COMPUTER SCIENCE

Personal Author(s):

Report Date:

1978-09-01

Pagination or Media Count:

178.0

Abstract:

In this dissertation, a new approach to the synchronization of accesses to shared data objects is developed. Traditional approaches to the synchronization problems of shared data accessed by concurrently running computations have relied on mutual exclusion -- the ability of one computation to stop the execution of other computations that might access or change shared data accessed by that computation. Our approach is quite different. We regard an object that is modifiable as a sequence of immutable versions, each version is the state of the object after an update is made to the object. Synchronization can then be treated as a mechanism for naming versions to be read and for defining where in the sequence of versions the version resulting from some update should be placed. In systems based on mutual exclusion, the timing of accesses selects the versions accessed. In the system developed here, called NAMOS, versions have two component names consisting of the name of an object and a pseudo-time, the name of the system state to which the version belongs. By giving programs control over the pseudo-time in which an access is made, synchronization of accesses to multiple objects is simplified.

Subject Categories:

  • Computer Hardware
  • Computer Systems
  • Manufacturing and Industrial Engineering and Control of Production Systems
  • Non-Radio Communications

Distribution Statement:

APPROVED FOR PUBLIC RELEASE