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From: Derek Fawcus <dfawcus+lists-tuhs@employees.org>
To: The Unix Heritage Society mailing list <tuhs@tuhs.org>
Subject: [TUHS] Onyx (was Re:  Unix on Zilog Z8000?)
Date: Tue, 21 Jan 2020 21:32:51 +0000	[thread overview]
Message-ID: <20200121213251.GA25322@clarinet.employees.org> (raw)
In-Reply-To: <CAC20D2MuKVqDdosO8FMZ52H1=GY=ziMUsFJsFoyVa0TAGwCx8A@mail.gmail.com>

On Tue, Jan 21, 2020 at 01:28:14PM -0500, Clem Cole wrote:
> The Onyx box redated all the 68K and later Intel or other systems.

That was a fun bit of grubbing around courtesy of a bitsavers mirror
(https://www.mirrorservice.org/sites/www.bitsavers.org/pdf/onyx/).

It seems they started with a board based upon the non-segmented Z8002
and only later switched to using the segmented Z8001.  In the initial
board, they created their own MMU:

  Page 6 of: https://www.mirrorservice.org/sites/www.bitsavers.org/pdf/onyx/c8002/Onyx_C8002_Brochure.pdf

  Memory Management Controller:

  The Memory Management Controller (MMC) enables the C8002 to perform
  address translation, memory block protection, and separation of
  instruction and data spaces. Sixteen independent map sets are
  implemented, with each map set consisting of an instruction map and
  a data map. Within each map there are 32 page registers. Each page
  register relocates and validates a 2K byte page. The MMC generates
  a 20 bit address allowing the C8002 to access up to one Mbyte of
  physical memory.

So I'd guess the MMC was actually programed through I/O instuctions
to io space, and hence preserved the necessary protection domains.

Cute.  I've had a background interest in the Z8000 (triggered by reading
a Z80000 datasheet around 87/88), and always though about using
the segmented rather than unsegmented device.

The following has a bit more info about the version of System III
ported to their boxes:

  https://www.mirrorservice.org/sites/www.bitsavers.org/pdf/onyx/c8002/UNIX_3.0.3_Software_Release_Notice_May83.pdf

DF

  parent reply	other threads:[~2020-01-21 21:33 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-21 17:52 [TUHS] Unix on Zilog Z8000? Jon Forrest
2020-01-21 18:13 ` Steve Nickolas
2020-01-21 18:27   ` William Pechter
2020-01-21 18:15 ` Henry Bent
2020-01-21 18:20   ` Larry McVoy
2020-01-21 21:48     ` Nigel Williams
2020-01-21 22:00       ` Henry Bent
2020-01-21 22:36         ` Derek Fawcus
2020-01-21 22:35     ` Jason Stevens
2020-03-15 18:40       ` Cornelius Keck
2020-03-16  0:28         ` Wesley Parish
2020-03-16 22:02           ` Derek Fawcus
2020-01-21 18:32   ` William Pechter
2020-01-21 21:24   ` Jon Forrest
2020-01-21 18:28 ` Clem Cole
2020-01-21 21:07   ` Heinz Lycklama
2020-01-21 21:32   ` Derek Fawcus [this message]
2020-01-22  8:18   ` Arrigo Triulzi
2020-01-22 17:00 ` Mary Ann Horton
2020-01-22 21:04   ` [TUHS] Life at UC Berkeley (was Unix on Zilog Z8000?) Jon Forrest
2020-01-23  2:08   ` [TUHS] Unix on Zilog Z8000? Erik Fair
2020-01-22 19:55 ` Andreas Hein
2020-01-23 12:01   ` Oliver Lehmann
2020-01-25  1:46     ` [TUHS] Dhrystone Benchmark (was: Unix on Zilog Z8000?) Oliver Lehmann
2020-01-25  1:49       ` Oliver Lehmann
2020-01-25  2:29         ` Warner Losh

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