From: jnc@mercury.lcs.mit.edu (Noel Chiappa)
To: tuhs@tuhs.org
Cc: jnc@mercury.lcs.mit.edu
Subject: [TUHS] Re: Split addressing (I/D) space (inspired by the death of the python... thread)
Date: Thu, 3 Aug 2023 17:48:21 -0400 (EDT) [thread overview]
Message-ID: <20230803214821.CEE3F18C07E@mercury.lcs.mit.edu> (raw)
> From: Will Senn
> Does unix (v7) know about the PDP-11 45's split I/D space through
> configuration or is it convention and programmer's responsibility to
> know and manage what's actually available?
There are two different cases: i) support of split I+D in the kernel, and
ii) support of split I+D in user processes. Both arrived with V6; the
V5 source:
https://minnie.tuhs.org/cgi-bin/utree.pl?file=V5/usr/sys/conf/mch.s
https://minnie.tuhs.org/cgi-bin/utree.pl?file=V5/usr/sys/ken/main.c
(former for kernel; later for users) shows no sign of it.
> From: Kenneth Goodwin <kennethgoodwin56@gmail.com>
> 1. I don't think the 11/45 had split I & d.
> But I could be wrong.
> That did not appear until the 11/70
You are wrong.
The chief differences between the KB11-A&-D of the -11/45 and the -B&-C of
the -11/70 were i) the latter had a cache, and ii) the latter used the 32-bit
wide Main Memory Bus, which also allowed up to 4 Mbytes of main memory.
Detail here:
https://gunkies.org/wiki/PDP-11/70
along with a couple of lesser differences.
> From: "Ronald Natalie"
> with only 8 segment registers combined for code, data, and stack
I think you meant for code, data, and user block.
> The 55 (just a tweaked 45)
The /50 and /55 had the identical KB11-A&-D of the /45; the difference was
that they came pre-configured with Fastbus memory.
> In addition the 23/24/J-11 and those derived processors did.
No; the F-11 processors did not support I&D, the J-11 did.
Noel
next reply other threads:[~2023-08-03 21:48 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-03 21:48 Noel Chiappa [this message]
-- strict thread matches above, loose matches on Subject: below --
2023-08-04 21:40 Noel Chiappa
2023-08-03 23:14 Steve Simon
2023-08-03 23:10 Noel Chiappa
2023-08-03 23:42 ` Warner Losh
2023-07-30 23:59 [TUHS] Re: Cool talk on Unix and Sendmail history, by Eric Allman Erik E. Fair
2023-08-01 10:58 ` Erik E. Fair
2023-08-02 0:37 ` Dave Horsfall
2023-08-02 14:52 ` Ron Natalie
2023-08-02 21:14 ` Grant Taylor via TUHS
2023-08-02 22:20 ` segaloco via TUHS
2023-08-02 23:49 ` Rich Salz
2023-08-03 0:51 ` [TUHS] Re: python Larry McVoy
2023-08-03 2:07 ` Clem Cole
2023-08-03 16:57 ` [TUHS] Re: [TULSA] " Phil Budne
2023-08-03 17:00 ` Rich Salz
2023-08-03 20:35 ` [TUHS] Split addressing (I/D) space (inspired by the death of the python... thread) Will Senn
2023-08-03 21:05 ` [TUHS] " Kenneth Goodwin
2023-08-03 21:10 ` Ronald Natalie
2023-08-03 21:16 ` Warner Losh
2023-08-03 21:24 ` Ronald Natalie
2023-08-03 22:34 ` Kenneth Goodwin
2023-08-03 21:05 ` Ronald Natalie
2023-08-03 21:44 ` Clem Cole
2023-08-03 22:08 ` Will Senn
2023-08-03 22:54 ` Clem Cole
2023-08-03 23:08 ` Dave Horsfall
2023-08-03 23:15 ` Clem Cole
2023-08-04 0:38 ` John Cowan
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