Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!husc6!think!ames!amdahl!oliveb!Roma!lance
From: lance@Roma.orc.olivetti.com (Lance Berc)
Newsgroups: comp.unix.wizards
Subject: Re: When did paging get into System V
Summary: Sun memory mapping never followed anything like the Vax model
Message-ID: <21757@oliveb.olivetti.com>
Date: 14 May 88 00:52:54 GMT
References: <53@lazlo.UUCP> <142700033@occrsh.ATT.COM> <651@pyuxe.UUCP> <382@cloud9.UUCP> <7878@brl-smoke.ARPA> <21688@oliveb.olivetti.com> <7885@brl-smoke.ARPA>
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Reply-To: lance@Roma.UUCP (Lance Berc)
Organization: Olivetti Research Center, Menlo Park, CA
Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!husc6!think!ames!amdahl!oliveb!Roma!lance
From: lance@Roma.orc.olivetti.com (Lance Berc)
Newsgroups: comp.unix.wizards
Subject: Re: When did paging get into System V
Summary: Sun memory mapping never followed anything like the Vax model
Message-ID: <21757@oliveb.olivetti.com>
Date: 14 May 88 00:52:54 GMT
References: <53@lazlo.UUCP> <142700033@occrsh.ATT.COM> <651@pyuxe.UUCP> <382@cloud9.UUCP> <7878@brl-smoke.ARPA> <21688@oliveb.olivetti.com> <7885@brl-smoke.ARPA>
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Reply-To: lance@Roma.UUCP (Lance Berc)
Lines: 33

In article <7885@brl-smoke.ARPA> gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>) writes:
>In article <21688@oliveb.olivetti.com> lance@Roma.UUCP (Lance Berc) writes:
>>In article <7878@brl-smoke.ARPA> gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>) writes:
>>>(Sun designed their original memory management hardware to look virtually
>>>the same as the VAX's, to avoid this.  Not everyone has had that option.)
>>The memory hardware of Vaxen and Suns (at least twos and threes) are
>>COMPLETELY different.
>
>While possibly true, it's irrelevant.  Notice the word "original" in my
>posting.  I have to admit I don't have "Sun-1" hardware documentation;
>my conclusion was drawn from perusing the memory management sections of
>the 4.1BSD source code as adapted to the original Sun computer.  By now
>both Sun and Berkeley have had time to improve the virtual memory model.
>My point was that it started out a VAX-specific mess.

SMI didn't design Sun-1 boards; they were designed for a DARPA VLSI
project at Stanford and were later involved in the Network Graphics
and SUN (Stanford University Network) projects. There was no thought
towards putting Unix (or any other OS, really) onto the hardware at
the time they were designed, though some Lucasfilm people did so. The
Sun-1s used 68000s only, so they had no virtual memory capability
whatsoever.  In addition, the page mapping hardware of the Sun-1
didn't look anything like a VAX, either (still no TLB, maps living in
fc3 space, not main memory, had only two levels of protection, etc).

I admit that programming Sun-[123] memory hardware can be a bit messy,
but it's never been a VAX sort of mess.

lance
Lance M. Berc			    Phone: (415) 496-6248
Olivetti Research Center            Internet: lance@orc.olivetti.com, or
2882 Sand Hill Road, Suite 210                lance%orc.uucp@unix.sri.com
Menlo Park, CA 94025                UUCP: {acornrc,oliveb,sri-unix}!orc!lance