[TUHS] Unix clones

Clem Cole clemc at ccc.com
Fri Apr 7 04:09:54 AEST 2017

s/DNS/DNA/    - dyslexia sucks....

On Thu, Apr 6, 2017 at 2:02 PM, Clem Cole <clemc at ccc.com> wrote:

> ​try-II sorry about that...​
> On Wed, Apr 5, 2017 at 9:18 PM, Wesley Parish <wes.parish at paradise.net.nz>
>  wrote:
>> The mention of UNOS a realtime "clone" of Unix in a recent thread raises
>> a question for me. How many
>> Unix clones are there?
> ​An interesting question....   I'll take a shot at this in a second, note
> there is a Wikipedia page: https://en.wikipedia.org/wiki/Category:Unix_
> variants that I don't fully agree with.
> The problem with all of this question is really depends where you place
> which boundary on the following continuum:
> non-unix                      add-unix ideas               trying to be
> unix              might as well be unix                       research unix
> stream
> eg  VMS                            eg Domain                    eg UNOS
>                       eg Sys V, BSD/386 & Linux              Vx & BSD VAX
> Different people value different things.  So here is my take from the
> "cloned" systems I used/was basically aware....
> Idris was a V6 clone for the PDP-11, which I saw 1978ish.   I can say I
> was able to recompile code from v6 and it "just worked"  so from a user's
> standpoint it might as well has been.   But the compilers and assemblers
> were different and I never tried anything "hard"
> The first attempt to "clone" v7 that I knew about was in France, and
> written in Pascal - I think at Ecole Tech in Paris?  The name of the
> project escapes me, but they presented the work in the 1979/80 winter
> USENIX (Blackhole) conference in Denver.  There were no proceedings in
> those days.  I believe it also ran on the PDP-11, but I never ran it so; so
> I have no idea how easy it was to move things from Seventh Edition.   But I
> also don't think they were working binary compatibility, so I think it
> landed more toward the center.
> The Cruds folks (Goldberg) wrote UNOS shortly there after (early 80s)
>  It was definitely not UNIX although it tried to have be mostly.   We had
> CRDS box at Masscomp and before I arrived they plan had been to use it get
> code working before the RTU was running.   But the truth was it failed
> because it was not UNIX.   The 68000 vs Vax issues were far, far less of an
> issue than UNOS != UNIX.  To Goldberg's credit, he did have a couple of
> cool things in it. I believe only system commercial systems that used
> Kanodia & Reed's Sequences and Eventcounts, were UNOS, Apollo Doman, and
> Stellar's Stellix (I'm not sure about DG - they might have also at one
> point).   But these were hidden in the kernel.  Also the driver model he
> had was different, so there was no gain writing drivers there.
> Mike Malcom & Dave Cheriton at Waterloo developed Thoth (Thoth - Thucks),
> which was written in B, IIRC.  Ran on the PDP-11 and was very fast and
> light.  It was the first "ukernel" UNIX-like/clone system..  Moving code
> from V7 was pretty simple and there was attempt to make it good enough to
> make it easy to move things, but it was not trying to be UNIX so it was
> somewhere in the middle.
> The Tunis folks seem to have been next.   This was more in the left side
> of the page than the right.   I think they did make run on the PDP-11, but
> I'm not so sure how easy it was to move code.   If you used their
> concurrent Pascal, I suspect that code moved.  But I'm not sure how easy it
> was to move a raw K&R "White Book" C code.
> CMU's Accent (which was redo of Rochester's RIG) came around the same
> time.   Like Tunis the system language was an extended Pascal and in fact
> the target was the triple drip Perq (aka the Pascalto).   The C compiler
> for it was late, and moving code was difficult, the UNIX influence was
> clear.
> Apollo's Aegis/Domain really came next - about 82/83 ish.   Like Accent it
> was written in hacked up Pascal and the command were in Ratfor/Fortran
> (from the SW Tool User's Group).    C showed up reasonably early, but the
> focus did not start trying to be UNIX.  In fact, they were very
> successfully and were getting ISV's to abandon VMS for them at a very good
> clip.   UNIX clearly influenced the system, but it was not trying to be
> UNIX, although moving code from BSD or V7 could be done fairly easily.
> Tannebaum then did MINIX.   Other than 8086 vs PDP-11-ism, it was a pretty
> darned good clone.    You could recompile and most things pretty much "just
> worked."   He did not support ptrace and few other calls, but as a basic V7
> system running on a pure PDP PC, it was remarkably clean.  It also had a
> large number of languages and it was a great teaching system - which is
> what Andy created it be.    A problem was that UNIX had moved on by the
> time Andy released it.   So BSD & V8 were now pretty much the definition of
> "UNIX" - large address spaces were needed.  As were the BSD tools
> extensions, such as vi, csh.   Also UUCP was now very much in the thing,
> and while it was a pure v7 clone, it was the lack of "tools" that made it
> not a good system to "use" and it's deficiencies out weighed the value.
> Plus as discussed elsewhere, BSD/386 would appear.
> Steve Ward's crew at MIT created TRIX, which was a UNIX-like, although
> instead of everything being a file, everything was a process.  This was
> supposed to be the system that rms was originally going to use for GNU, but
> I never knew what happened.   Noel might.  I thought it was a cool system,
> although it was a mono-kernel and around this time, most of the OS research
> had gone ukernel happy.
> Coherent was announcement and its provenance is questioned, although as
> discussed was eventually released from the AT&T official inquiry and you
> can look it your self.   It was clearly a V7 clone for the PC and was more
> complete than Minix.  I also think they supported the 386 fairly quickly,
> which may have made it more interesting from a commercial standpoint.  It
> also had more of the BSD tools available than Minix did when it was first
> released.
> CMU rewrites Accent to create Mach, but this time splices the BSD kernel
> inside of it so that the 4.1BSD binaries "just work."   So it's bit UNIX
> and a new system all in one.  So which is it?   This system would begat
> OSF/1 and eventually become Apple's Mac OS?   I think its UNIX, but one can
> claim its not either....
> By this point in time the explosion occurs.   You have Lion's book, Andy's
> and Maury Bach's book on the street. he genie is clearly out of the bottle,
> and there is a ton of code out there and the DNS is getting all mixed up.
> Doug Comer does Xinu, Sheraton does V-kernel, Thoth is rewritten to become
> QNX, and  a host of others I have not repeated.  BSD's CSRG group would
> break up, BSDi would be created and their 386 code come out.   It was
> clearly "might as well be" if it was not.  Soon, Linus would start with
> Minix and the rest is history on the generic line.
> Clem
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