From: jnc@mercury.lcs.mit.edu (Noel Chiappa)
Subject: [TUHS] v6tar from v7 on v6, too large?
Date: Wed, 9 Dec 2015 00:17:20 -0500 (EST) [thread overview]
Message-ID: <20151209051720.4C6D218C0C5@mercury.lcs.mit.edu> (raw)
> From: Noel Chiappa
> the most likely is that 'v6tar' is linked to be split I+D, and your V6
> emulation is on a machine that doesn't have split I+D (e.g. an 11/40)
Now that I think about it, the linked systems that are part of the V6 distro
tape are all linked to run on an 11/40. They will boot and run OK on a more
powerful machine (/45 or /70), but they will act like they are on a /40 -
i.e. no split I+D support/use (user or kernel). So to get split I+D support,
you need to build a new Unix binary, with m45.s instead of m40.s. If you
haven't done that, that's probably what the problem is.
Aside: V6 comes in two flavours: no split I+D at all, or split I+D in both
the kernel and user. For some reason that I can't recall, we actually
produced an 'm43.s', BITD at MIT, which ran the kernel in non-split-I-D, but
supported split I-D for the users.
I wish I could remember why we did this - it couldn't have been to save
memory (the machine didn't have a great deal on it when this was done -
although I have this vague memory that that was why we did it), because
running split I+D in the kernel does not, I think, use any more physical
memory (provided you don't fiddle with the parameters like the number of
buffers) than running non-split. Or maybe it does?
One possible reason was that the odd layout of memory with split I+D in the
kernel made debugging kernel code harder (we were doing a lot of kernel
hacking to support early networking work); another was that we were just being
conservative, didn't need to extra space in the kernel that I+D allowed, and
so didn't want to run it.
Noel
next reply other threads:[~2015-12-09 5:17 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-09 5:17 Noel Chiappa [this message]
2015-12-09 5:55 ` Mark Longridge
2015-12-09 11:31 ` Ronald Natalie
-- strict thread matches above, loose matches on Subject: below --
2015-12-19 13:27 Noel Chiappa
2015-12-10 4:50 Noel Chiappa
2015-12-09 22:16 Noel Chiappa
2015-12-09 22:31 ` Clem Cole
2015-12-09 22:47 ` John Cowan
2015-12-09 23:39 ` Steve Nickolas
2015-12-10 0:24 ` Clem Cole
2015-12-10 0:23 ` Clem Cole
2015-12-10 1:08 ` Greg 'groggy' Lehey
2015-12-10 9:42 ` Jacob Ritorto
2015-12-10 1:19 ` John Cowan
2015-12-10 10:06 ` Oliver Lehmann
2015-12-10 19:50 ` Will Senn
2015-12-09 22:01 Noel Chiappa
2015-12-09 17:50 Noel Chiappa
2015-12-09 18:06 ` Will Senn
2015-12-09 14:56 Noel Chiappa
2015-12-09 16:37 ` Will Senn
2015-12-09 14:24 Noel Chiappa
2015-12-09 13:30 Noel Chiappa
2015-12-09 14:43 ` Ronald Natalie
2015-12-09 20:41 ` Dave Horsfall
2015-12-09 4:53 Noel Chiappa
2015-12-09 14:38 ` Will Senn
2015-12-09 14:56 ` Clem Cole
2015-12-09 15:07 ` Clem Cole
2015-12-09 16:29 ` Will Senn
2015-12-09 14:59 ` Hellwig Geisse
2015-12-09 17:55 ` Will Senn
2015-12-09 3:33 Will Senn
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20151209051720.4C6D218C0C5@mercury.lcs.mit.edu \
--to=jnc@mercury.lcs.mit.edu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).