Wraith Scheme 1.32 released (for Macintosh); does parallel processing
Jay Reynolds Freeman
Scheme implementation for the Apple Macintosh, with enhancements for
parallel processing, by which I mean multiple copies of the Wraith
Scheme application (separate Unix processes) all running at once,
sharing Scheme main memory. For details, and to download a copy,
visit the software page of my website:
Main website: http://web.mac.com/jay_reynolds_freeman
Software page: http://web.mac.com/jay_reynolds_freeman/iWeb/My/Software.html
The software page includes a link to a web-browsable copy of the
Wraith Scheme Help file, a and more specific link to the part of that
file that discusses parallel processing.
Wraith Scheme 1.32 is a bug-fixer for Wraith Scheme 1.31.
I have done a major rewrite of the low-level locking mechanisms which
prevent simultaneous actions by separate Wraith Scheme processes from
corrupting Wraith Scheme's shared main Scheme memory.
The war story here is, that I had done previous testing of the
parallel implementation of Wraith Scheme on a Macbook 13, that only
had two processor cores and in fact ran relatively little code in
parallel -- it mostly swapped. In late January, 2008, I bought a high-
end Mac Pro, with eight cores; it was more than capable of running
several Wraith Scheme processes in parallel, and "shook the tree"
sufficiently hard thereby, to expose a handful of bugs that had
escaped earlier testing.
They were tough bugs, involving commmunications and locking between
multiple asynchronous processes, and in general never repeated
themselves the same way twice. It took three months to get things
back to stable. I don't ever want to do that again, but I fear that I
shall have to.
-- Jay Reynolds Freeman
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Jay_Reynol...@mac.com
http://web.mac.com/jay_reynolds_freeman (personal web site)