From: wkt@minnie.tuhs.org (Warren Toomey)
Subject: [TUHS] Other operating systems on the PDP-11
Date: Mon, 8 Jul 2002 13:43:51 +1000 (EST) [thread overview]
Message-ID: <200207080343.g683hqX97846@minnie.tuhs.org> (raw)
In-Reply-To: <20020708025934.GH90012@wantadilla.lemis.com> from "Greg 'groggy' Lehey" at "Jul 8, 2002 12:29:34 pm"
In article by Greg 'groggy' Lehey:
> Has anyone successfully gotten, say, NetBSD, or anything along the lines of the
> > 4.4 series to run on a PDP-11?
>
> The big issue is address space. It's difficult enough shoehorning
> 2.11BSD onto the PDP-11. It's well-nigh impossible to retrofit 32 bit
> operating systems. But Steven M. Schulz will doubtless give you a
> better explanation.
> Greg
More specifically, the issue is data space. Using overlays, you can
have a process with more than 64Kbytes of instruction space on a PDP-11,
but the maximum data space that a process can have is 64Kbytes.
The kernel is in a similar situation, but with some PDP-11 models
there is kernel mode and supervisor mode, giving you two separate
64Kbytes instruction + 64Kbytes data address spaces (and overlays
to increase the I space).
I can't see Linux fitting into 128K of data space, and GCC is definitely
out of the question. Besides, 2.11BSD already looks pretty close to 4BSD :-)
Warren
next prev parent reply other threads:[~2002-07-08 3:43 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-07-08 2:53 Gregg C Levine
2002-07-08 2:59 ` Greg 'groggy' Lehey
2002-07-08 3:43 ` Warren Toomey [this message]
2002-07-08 4:30 Steven M. Schultz
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=200207080343.g683hqX97846@minnie.tuhs.org \
--to=wkt@minnie.tuhs.org \
/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).