Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ukma!rutgers!caip.rutgers.edu!segall From: segall@caip.rutgers.edu (Ed Segall) Newsgroups: comp.lang.smalltalk Subject: Re: parallelism in ST-80 Message-ID: Date: 20 Apr 89 21:50:03 GMT References: <3736@sdsu.UUCP> Organization: Rutgers Univ., New Brunswick, N.J. Lines: 25 Smalltalk has provisions for concurrent execution, but not parallelism. In other words, you can simulate parallel operation, but everything actually happens sequentially. Semaphores, forked processes and shared queues are reasonable to work with for simulating parallelism. Just remember that things will go quite slowly - you are simulating the work of many processors! Caveat: watch out for scheduling. The default scheduler in ST80 is not a fair scheduler - you have to make sure your processes stop in order for others at the same or lower priority to run. Thus, you have to resort to some artificial tricks to simulate true concurrency. There are versions of smalltalk or code in smalltalk that people are working on which support concurrent programming much more directly. See the April 89 issue of SIGPLAN notices for the proceedings of the ACM SIGPLAN workshop on object-based concurrent programming for more information. --Ed -- uucp: {...}!rutgers!caip.rutgers.edu!segall arpa: segall@caip.rutgers.edu