Abstract

Topaz is an experimental distributed computing environment programmed in Modula-2+, which supports garbage collection. Topaz has been in daily use by about 50 researchers at SRC since 1986. The Modula-2+ garbage collector is concurrent; it combines reference-counting and mark-and-sweep collection. The principal challenges are to reduce the costs of the language primitives, and to reduce the time spent in the collector. (This position paper contains material from references [4] and [5].) 1 Background The Topaz experience illustrates how it is possible to extend a systems implementation language with garbage collection, and successfully use it to build a large software environment. Modula-2+ [9] is the main systems implementation language at Digital Equipment Corporation's Systems Research Center (SRC). Modula-2+ is an extension of Modula2 [11]; it adds language support for concurrency, exceptions, and garbage collection. In particular, Modula-2+ adds the REF type constructor, which gen...

Citations

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