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From: lindsay@gandalf.cs.cmu.edu (Donald Lindsay)
Newsgroups: comp.arch
Subject: Re: Porting OSes (was DEC RISC Architecture)
Message-ID: <10734@pt.cs.cmu.edu>
Date: 12 Oct 90 00:56:20 GMT
References: <4462@trantor.harris-atd.com> <107038@convex.convex.com> <15007@hydra.gatech.EDU>
Organization: Carnegie-Mellon University, CS/RI
Lines: 30

In article <15007@hydra.gatech.EDU> ken@dali.gatech.edu 
	(Ken Seefried iii) writes:
>I believe that DEC has already announced that it is deep into a
>project to port VMS to the MIPS machines.

The whole idea of porting an OS was new in the mid-70's: most of us
hadn't even considered it, until the first Unix port took place.
Unix was suitable, not because its developers had allowed for that -
they hadn't - but because it was well done, and mostly not in
assembler.  But Multics (written in PL/I) was well done, and so was
MCP (written in Burroughs Extended Algol).  Why Unix?

Perhaps the biggest (non-political) point was that Unix didn't expect
much from the underlying machine.  The PDP-11 didn't have much to
give!

When the VAX design was started, there were people at DEC who wanted
to build some flavor of capability/domain machine.  It would have
been exciting: it would have been risky.  The design group finally
settled for something that they knew they could make work. It's
really quite ironic that their design is now used as an example of
complexity.

An important consequence is that VMS doesn't expect much from a VAX.
And that's why the Mach group at CMU can plan to build a VMS "server"
to run on the Mach pure kernel, just as their Unix server does.

I think there's a moral here somewhere.
-- 
Don		D.C.Lindsay