I've assembled some notes from old manuals and other sources
on the formats used for on-disk file systems through the
Additional notes, comments on style, and whatnot are welcome.
(It may be sensible to send anything in the last two categories
directly to me, rather than to the whole list.)
I've already posted all sorts of information previously, but the
thread seems to have gotten caught in some downtime over the weekend.
Anyway, does anybody have any idea what I might be doing wrong?
Prior posts are in the web archive.
Michael "Madcrow" K.
> Message: 1
> Date: Wed, 14 Jun 2006 16:24:29 -0700 (PDT)
> From: Martin Lovick <martin_lovick(a)yahoo.com>
> Subject: [pups] bitsavers document
> To: pups(a)minnie.tuhs.org
> Message-ID: <20060614232429.78414.qmail(a)web36905.mail.mud.yahoo.com>
> Content-Type: text/plain; charset=iso-8859-1
> whilst looking around the bitsavers.org pdf archive, I
> found a document called
> Having had a quick scan through, it contains a source
> code listing and some commentary (lions i hear you
No, not Lions. The author is listed on the first page as one T. R.
> The strange thing is that all of the source code
> appears to be in assembler...
yup. This would be an early pdp11 UNIX from the period before the
rewrite in C.
> whats this about?
It appears to be a listing of an assembly language version of an
early UNIX kernel for the pdp11 in the pages labelled E*-*; the pages
F*-* are a commentary; G*-* is a glossary of terms used; H*-*
contains a description of each function in the kernel with complete
details of each function.
> is it a comentary of PDP-7 unix?
It's (Bell Labs flavor) pdp11 assembly language.
Milo Velimirović <milov(a)uwlax.edu>
Unix Computer Network Administrator 608-785-6618 Office
ITS Network Services 608-386-2817 Cell
University of Wisconsin - La Crosse
La Crosse, Wisconsin 54601 USA 43 48 48 N 91 13 53 W
Unix: Where /etc/init is job #1.
I downloaded the tape building kit of Fred's enhanced Ultrix 3.1 and
set about trying to build an image file suitable for use with SIMH. As
simply modifying the included script to write to a normal file instead
of a (non-existant) tape device failed, I tried doing things by hand,
running maketape and then "cat"ing the file it created along with all
the other files "dd"ed by the script into a single file. While this
produced a file that looked about the right size, it didn't work with
SIMH as mounting it to the emulated TK50 device and booting produced:
HALT instruction, PC: 016300 (CLR R3)
Any help on how to get a working image available so that my nerdy
history project can proceed?
Mike "Madcrow" K.
> I tried doing things by hand,
> running maketape and then "cat"ing the file it created along with all
> the other files "dd"ed by the script into a single file.
You need to put file marks between everything logically 'dd'-ed
In the .tap format, file marks are four bytes of 0.
End of tape should have two sets of file marks (eight bytes of 0)
FWIW, I sent warren a .tap image of Ultrix 2.0. Never heard anything from
him about it.
Actually what I meant Gregg was Jon Pertwee was the Doctor back in the
'60s which is the time period you were referring to, and Troughton too I
guess. That reminds me of an episode called "The time..." something or other
with Roger Delgado. They were trying to do something with some type of
computer obviously an old mini of some type and some anciet artifact. There
were toggle switches and lights. Otherwise it certainly didn't look like and
PDP that I've ever seen in pictures. Just to get close to one of those old
things would be breathtaking. Before my time though.
I have here a Doctor Who book which takes place during the early part of the
computer revolution, about the time the whole of what's discussed here
happened. The people concerned in the book have machines running UNIX. Some
of these are indeed PDP-11s and there are also a few DG Eclipses.
Now the question: How difficult would it to port UNIX V7 from the usual
machine, probably a PDP-11/43 (But I might be wrong about the model!) to a
DG Eclipse? Naturally since I don't have physical hardware here, the
intended target would be a SIMH DG virtual Eclipse (Or even a Nova 4) and
the one doing all the work would be a SIMH PDP-11.
Gregg C Levine hansolofalcon(a)worldnet.att.net
"The Force will be with you. Always." Obi-Wan Kenobi