Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!usc!ucsd!ucsdhub!hp-sdd!ncr-sd!ncrcae!hubcap!larsa From: larsa@nada.kth.se (Lars Andersson) Newsgroups: comp.parallel Subject: using network machines as compute servers Message-ID: <7278@hubcap.clemson.edu> Date: 1 Dec 89 13:55:07 GMT Sender: fpst@hubcap.clemson.edu Lines: 47 Approved: parallel@hubcap.clemson.edu Dear NET! I want to develop (or rather: I want some one to give me :-) ) a few SIMPLE tools to use for building "compute servers" running on a set of machines connected in a network. I'm talking about coarse grained parallelism here but I guess this is relevant also for shared memory and hypercube type machines. I'm sure there are a number of ways to approach this problem and even a number of solutions around, but faced with the rather bewildering fauna of "parallel operating systems", models for parallel computations etc. (LINDA, ISIS, Cosmic Environment, MACH (?) ...) one becomes reluctant to invest work in any one of these, without knowing which will have the broadest base in the near future. There is a large class of problems that can require a huge number of similar, SCALAR DOMINATED, calculations be carried out, with perhaps a periodic gathering and analysis of the solutions. Hence for the parallel subproblems, vectorization is not interesting, nor is communication speed between the processors critical. I believe this is called trivial parallelism. In this situation, one doesn't really care what machine the thing runs on as long as one is able to access as many cheap CPU cycles as possible, such as the joint resources of the local net. What I have in mind is therefore solutions which allow one to run the subproblems on machines with different architecture, not necessarily with a common NFS server. Consider the following: One "master" puts "tasks" in a batch, there to be picked up by the "slaves" as each completes its current task. When a slave completes a task it puts the solution in an appropriate batch, there to be picked up and stored by the master (depending on the problem, one might want to write directly to a file ...). Within my limited knowledge, the only system that has something like this "built in" is ISIS (the NEWS service). However, it's not clear to me that this is correct or suited for this kind of application, or if it's the only or best (most portable) solution. Any comments on the above would be appreciated. In particular, examples or code fragments pertaining to this situation would be gratefully recieved. Where lies the future? Yours, Lars Andersson larsa@math.kth.se disclaimer: I'm a mathematician, not a computer scientist. Brought to you by Super Global Mega Corp .com