[TUHS] Setting Up UNIX—Sixth Edition: An OpenSIMH Laboratory for Reading Lions

[christopher fujino via TUHS]

Oh nice, this is great! I'm definitely a pdp-11/simh n00b, so I think I
would be a good guinea pig. I will try this today and share if I have any
actionable feedback.

Chris

On Fri, Jul 24, 2026 at 11:33 AM Will Senn via TUHS <tuhs at tuhs.org> wrote:

> Hi all,
>
> I support the proposed IEEE Milestone recognizing John Lions' UNIX
> Operating System Source Code Level Six and A Commentary on the UNIX
> Operating System. Few works have had a comparable influence on operating
> systems education, and it is fitting to see them considered for formal
> recognition.
>
> With that discussion underway, I thought I would mention a companion
> resource I have just completed.
>
> For the past several years, I have been working with V6 under OpenSIMH
> for a variety of purposes, and I have written up the general
> installation and customization process before. This is not another of
> those notes. Setting Up UNIX—Sixth Edition: An OpenSIMH Laboratory for
> Reading Lions is written in the genre of Thompson and Ritchie's original
> memo: a procedure, in their register, addressed to someone assembling a
> specific machine and environment. Its scope is both narrower than theirs
> and broader. It constructs a modern virtual counterpart to the
> laboratory in which Lions' students worked. An installation guide ends
> at a login prompt, but this guide goes further: to a correspondence
> among the running kernel, the source tree from which it was built, and
> the listing Lions annotates, all resolvable against one another.
>
> The original laboratory required a PDP-11/40, controllers, several RK05
> drives, magnetic tape, terminals, a printer, removable media, and the
> accompanying source and documentation. In the reconstructed laboratory,
> those components take different forms. OpenSIMH supplies the processor,
> memory, controllers, and peripheral devices. The distribution tape and
> removable disk packs are represented by image files, while a modern
> terminal program provides access to the running system. The cabinets,
> motors, reels, and 14-inch platters have disappeared, but the interfaces
> presented to V6 remain those of the original machine. V6 does not know
> the difference.
>
> The guide leads readers who want to study Lions in a working laboratory
> environment through restoring the original V6 distribution from tape,
> rebuilding the kernel, installing the complete source and documentation
> filesystems, creating the required device files, verifying the
> installation, and producing a restorable baseline archive. The completed
> laboratory is configured to match the presumed model system described by
> Lions on page 1-2 of the Commentary. It allows readers to boot the
> system, examine the installed source, rebuild the kernel, and move
> directly among the running system, the source deployed from the original
> distribution tape, and the edited listing published as UNIX Operating
> System Source Code Level Six.
>
> The guide is intended to be used together with my updated and expanded
> edition of UNIX Operating System Source Code Level Six, which preserves
> Lions' original sheet numbering while adding file locations, procedure
> listings, indexes, cross references, and configured-kernel symbol tables
> keyed to the delivered source code. Together, the two resources make it
> possible to read Lions not only as a historical text, but against a
> living V6 system assembled from the original distribution materials.
>
> Guide:
>
> https://decuser.github.io/posts/setting-up-unix-sixth-edition-opensimh-laboratory-for-reading-lions/
>
> Companion source edition:
>
> https://decuser.github.io/posts/updated-lions-v6-source-w-appendices-and-helps-v1.4/
>
> The guide takes me about 15 minutes to work through now, but I expect a
> careful first reading and installation will take a couple of hours.
>
> I would be glad to hear from anyone who takes a look, even if only to
> let me know you had a chance to read it. Corrections, questions, and
> suggestions are especially welcome.
>
> Regards,
> Will
>