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.)
Hello, all: I'm working (long-term) on a project to bring back to life the
V6+ Unix system (it wasn't vanilla V6 - it looks like it had some PWB stuff
added) that was used on a number of machines at the Laboratory for Computer
Science at MIT in the late 70s - early 80s.
As part of that, I've been playing with bringing up V6 on a PDP11 simulator,
and have written some stuff that would probably be useful to anyone who's
interested in bringing up Unix on a PDP-11 simulator.
I used the Ersatz-11 simulator from D-Bit (for no particularly good reason,
except it runs under Windoze, and the "FAQ on the Unix Archive and Unix on
the PDP-11" page said it was the fastest).
I have been very pleased with this simulator; it is indeed fast (my simulated
11/70 runs at about 100 MIPS on a relatively elderly Athlon, which is about
30 times as fast as a real one used to :-), and it has lots of nice features
(e.g. you can TELNET in to a terminal port on the simulated PDP-11).
It also has this nice virtual device that allows a program running on the
simulated PDP-11 i) access to files in the Windows file system, and ii) to
issue commands to the emulator. I have written a V6 driver for it (should be
fairly easy to adapt to V7 or later), and a suite of Unix commands to grab a
file off the Windows file system (both binary and text mode), and issue
various commands to the simulator.
Finally, I have a number of Windows commands to do various useful things,
such as read a file off a simulated Unix V6 file system (hosted in a Windows
file), including ports of a number of Unix commands (e.g. ncheck, nm, etc); I
don't detail them all here as I don't want this email to get too long (and
I'm not sure if anyone's interested in any of this; if so, I can send
in more info (or whip up a Web page, whichever would be better).
I also ran into a number of pitfalls on the way to getting V6 running, using
RK05 disk images from the TUHS archive, and I can do a short writeup on 'How
to bring up V6 under Ersatz-11' if anyone's interested.