University of Pennsylvania
ScholarlyCommons
Departmental Papers (CIS)
Department of Computer & Information Science
August 1987
Adding Time to Synchronous Process
Communications
Insup Lee
University of Pennsylvania, lee@cis.upenn.edu
Susan B. Davidson
University of Pennsylvania, susan@cis.upenn.edu
Follow this and additional works at: http://repository.upenn.edu/cis_papers
Recommended Citation
Insup Lee and Susan B. Davidson, "Adding Time to Synchronous Process Communications", . August 1987.
Copyright 1987 IEEE. Reprinted from IEEE Transactions on Computers, Volume C-36, Issue 8, August 1987.
This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of the
University of Pennsylvania's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this
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This paper is posted at ScholarlyCommons. http://repository.upenn.edu/cis_papers/383
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Adding Time to Synchronous Process Communications
Abstract
In distributed real-time systems, communicating processes cannot be delayed for arbitrary amounts of time
while waiting for messages. Thus, communication primitives used for real-time programming usually allow the
inclusion of a deadline or timeout to limit potential delays due to synchronization. This paper interprets timed
synchronous communication as having absolute deadlines. Various ways of implementing deadlines are
discussed, and two useful timed synchronous communication problems are identified which differ in the
number of of participating senders and receivers and type of synchronous communication. For each problem,
a simple algorithm is presented and shown to be correct. The algorithms are shown to guarantee maximal
success and to require the smallest delay intervals during which processes wait for synchronous
communication. We also evaluate the number of messages used to reach agreement.
Keywords
Ada, CPU, deadline, distributed system, real-time system, synchronous communication, timed synchronous
communication
Comments
Copyright 1987 IEEE. Reprinted from IEEE Transactions on Computers, Volume C-36, Issue 8, August 1987.
This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way
imply IEEE endorsement of any of the University of Pennsylvania's products or services. Internal or personal
use of this material is permitted. However, permission to reprint/republish this material for advertising or
promotional purposes or for creating new collective works for resale or redistribution must be obtained from
the IEEE by writing to pubs-permissions@ieee.org. By choosing to view this document, you agree to all
provisions of the copyright laws protecting it.
This journal article is available at ScholarlyCommons: http://repository.upenn.edu/cis_papers/383