[TUHS] Possible Assembly UNIX Kernel Images (s1-bits cunix/wunix)?

[segaloco via TUHS]

Thank you so much Briam!  I'll be sitting down to look more at the two
kernels later and will get this merged into v2src as well.  Fittingly I
have a house call to fix an old WECo phone so have to break from the
excitement for a few hours.  Do you have a preference on how I credit
you for this work in the README?

- Matt G.

On Friday, January 16th, 2026 at 14:11, Briam Rodriguez via TUHS <tuhs at tuhs.org> wrote:

> Hi Matt,
> 
> Saw your post about the v2src restoration project. I took a crack at
> disassembling the remaining binaries from the s2-bits tape -
> specifically the bin/ directory utilities.
> 
> I've got 26 commands disassembled and formatted to match your existing
> style conventions:
> 
> as, bas, cc, db, dc, ds, du, ed, fc, find, form, ld, maki, mv, nm, od,
> pr, roff, size, sort, stat, tap, tm, un, wc, who
> 
> They're ready as a patch file. Please find it attached. I tried creating
> a PR on gitlab but it wouldn't let me due to auth issues.
> 
> Happy to help with more disassembly work if there are other artifacts
> worth looking at.
> 
> -- Briam R.
> 
> On 1/16/26 5:06 PM, segaloco via TUHS wrote:
> 
> > Hello everyone, I've been picking back up on some of my V2/V3 era
> > reverse engineering efforts, picking through stuff from the Dennis_Tapes
> > archive, and I came across something I don't think I've seen discussed.
> > 
> > On the s1 tape, which we've yoinked a lot of V3 userland sources from,
> > there are files cunix and wunix. Upon some disassembly and inspection,
> > I believe these may be assembly UNIX kernels, although I haven't dug
> > around too much to see what version they match most closely. Here are
> > some findings that support my suspicions:
> > 
> > - Both files begin with a 407 magic number, making them V2 a.out
> > binaries.
> > - Both begin with a branch that jumps over a few things then calls a
> > subroutine. That subroutine matches "copyz" from u3.s in the scanned
> > V1 kernel description from BTL. Indeed this jump in that kernel is also
> > to copyz.
> > 
> > Of course, this is only the first few bits executed, but I would be
> > surprised to find such a close match elsewhere in the system. I do this
> > sort of analysis on old video game code all the time, so I feel pretty
> > confident in identifying these as possible assembly-era kernels.
> > 
> > Anyone dug around in these before? These should be PDP-11/20 kernels as
> > I'm finding plenty of EAE references, just like the s2-bits V2 binaries.
> > What I'm hoping to find here are bits that might indicate KS11 support,
> > what with the recent chit chat about KS11 in the V2 kernel.
> > 
> > - Matt G.