Lemma: A distributed shared memory with global and local garbage collection

Abstract

Standard ML is an established programming language with a well-understood semantics. Several projects have enriched the language with primitives or constructions for concurrency, among them Poly/ML and LCS. We describe first the previous run-time systems for Poly/ML and LCS and then the development of a new memory management system, LEMMA, which allows parallel programs to be run on networks of workstations. LEMMA provides a distributed shared virtual memory with global garbage collection, and in addition allows each machine to run independent local collections. LEMMA is written as a separate layer from the run-time systems of Poly/ML and LCS and is independent of the object representations and process management schemes used in the languages. We give a description of LEMMA and the results of the execution of some preliminary test programs.