HELP! * GREY=local LOCAL HTML version of Foils prepared July 6,1995

Foil 56 MOVIE -- 4: Communication Model and Preemptive Structure

From Master Foils for Threads with TCE in detail CPS600 Spring Semester95 -- April 1995. by Janusz Niemiec and Geoffrey Fox * See also color IMAGE
The MOVIE communication model is very similar to the discussed previously TCE model. Standard, task--wide ports are used to construct inter-task channels, and these are the base for constructing channel sets. Different modes of communication can be imposed on channels. But unlike TCE, in MOVIE there is no need to instruct the interpreter what kind of data is being sent of received. The system is object-oriented, so this information is already available to the network subsystem. Instead of a poorly formatted chunk memory, the formatted object is being sent. At the receiving end, a copy of that object is reconstructed and passed to an appropriate channel.
The MOVIE system is preemptive at the interpreted level. It means that no C-level code is being preempted. A context switch can take place between two operators, when the interpreter discovers that either IO or clock flags have been set. This solution is more efficient and allows a simpler implementation. The drawback is that the system cannot react immediately while executing an operator, thus some required time constraints may not be met.

Northeast Parallel Architectures Center, Syracuse University, npac@npac.syr.edu

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