[mod.ai] Seminar - Multilisp

Karen.Olack@H.CS.CMU.EDU.UUCP (03/10/87)

Speaker:	Robert Halstead
Date:		March 16, 1987
Time:		2:00 p.m.
Place:		Wean Hall 8220
Topic:		Multilisp:  A Language for Parallel Symbolic Computing

				ABSTRACT

Multilisp is an extension of Scheme with additional operators and
additional semantics for parallel execution.  These have been added
without removing side effects from the language.  The principal
parallelism construct in Multilisp is the "future," which exhibits some
features of both eager and lazy evaluation.  Current work focuses on
making Multilisp a more humane programming environment, on expanding the
power of Multilisp to express task scheduling policies, and on measuring
the properties of Multilisp programs with the goal of designing a
parallel architecture well tailored for efficient Multilisp execution.

Multilisp has been implemented, and runs on the shared-memory
Concert multiprocessor, using as many as 27 processors.  The
implementation uses interesting techniques for task scheduling and
garbage collection.  The task scheduler helps control excessive resource
utilization by means of an unfair scheduling policy; the garbage
collector uses a multiprocessor algorithm modeled after the incremental
garbage collector of Baker.

The talk will briefly describe Multilisp, discuss the areas of
current activity, and indicate the future direction of the project in
the areas of language design, application development, and
multiprocessor architecture.