What to Do with a PS/2?

John Wallace johnwallace4 at yahoo.co.uk
Thu Jan 28 13:54:11 CST 2016

[massive snippage, sorry]

Several folks have mentioned Dave Cutler.

There's a book called "Inside Windows NT", by Helen Custer at Microsoft Press. The aforementioned Dave Cutler (architect of software including RSX11, VAX/VMS, VAXELN, and WNT) wrote a foreword for it. There, he says the goals of NT were "portability, security, POSIX compliance, compatibility, scalable performance, multiprocessor support, extensibility, and ease of internationalisation" (p xviii in my copy). Obviously some of that list has fallen away during the NT/Gates years (portability? security? POSIX?)

WNT's kernel stuff, process architecture, etc has some VAXELN heritage. VAXELN was a not particularly well known (even inside DEC) Cutler project for a distributable realtime OS which would feel comfortable for VMS programmers without being VMS, and allow distributed RT applications to be developed without need to understand low level hardware specifics and OS kernel interface details. VAXELN incorporated early examples of a process model which also incorporated threads, and a nice approach to interprocess data sharing (a distributed naming service, transparent messaging between apps whether on the same node or separate, etc). Marvellous stuff, some of which  duly made its way into NT, though many writers understandably missed the VAXELN connection (it is briefly mentioned in Custer's book).

Those who are moderately familiar with the internals of NT, VMS, and VAXELN (which probably isn't that many people) will recognise some of the VMSisms that VAXELN didn't have and which are also not present in NT. At a detail level, where are WNT's ASTs, where are logical names? And at a big-picture level - VMS is a mostly monolithic setup (one single kernel address space), WNT originally wasn't, though over time Gates forced changes towards the monolithic approach, e.g. moving assorted drivers and subsystems into the kernel for performance reasons that for security and robustness reasons should have been isolated from each other. Neither VAXELN nor NT have quotas or privileges as such. There is no meaningful security architecture on WNT; on VMS there is. And so on.

But fewer people will know VAXELN, and so the Cutler project that gets the publicity in the "where does WNT come from" context is VMS (it is, after all, still pretty close even if VAXELN is closer).

And the WNT name? Who knows. 

The magic words PRISM and MICA perhaps come into this discussion somewhere too, but I know nothing about them.

Have a lot of fun.

John Wallace (not to be confused with John Willis!)

[Repurposed with minor edits from some of my occasional WNT/VAXELN/VMS ramblings on comp.os.vms]

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