[TUHS] shared memory on Unix

Nick Downing downing.nick at gmail.com
Thu Feb 2 10:25:56 AEST 2017

A very incisive post Clem and to everyone generally I am fascinated to hear
about PWB, Unix 3/4/5 history, System V, choice of codebases, featuresets
and APIs. The thread made a good read on a long boring drive and I'm not
even finished reading yet. :) Nick

On 02/02/2017 6:31 AM, "Clem Cole" <clemc at ccc.com> wrote:

> On Wed, Feb 1, 2017 at 1:33 PM, <arnold at skeeve.com> wrote:
>> ​..
>> At the time, the policy was to release externally one version
>> behind what was being run internally, so System III was released to the
>> world while the Bell System was using Unix 4.0.  I still have the manual;
>> I'm pretty sure "PWB" and "Programmer's Workbench" are not on the cover,
>> ​ ​
>> it was just called "UNIX".
> ​Could be.... the "System III" manual cover I have says PWB 3.0​
> I never had a 4.0 doc, although I saw it at some point.
>> As UNIX 5.0 was approaching, someone decided that to be one release
>> behind on the outside was dumb, thus the jump from System III to System
>> ​​
>> V.
> ​Making the outside and inside system in sync makes sense and I think I
> remember some of that.   But the name was definitely forced by the
> Marketing types in NC.  I somewhere have a memo that they sent to all
> licenses about the term UNIX and how it could be used and what could be
> called same.    It was clear that was all part of the UNIX wars and they
> were trying to make System xxx have some sort of halo.
> As a side note, what is funny is when it all went down, I remember having
> an argument with some of the Masscomp (and ex-DEC) marketing types.   The
> geeks (like me) just could not get through to them that what mattered was
> how it worked and what was inside (which BSD was pretty much superior
> technology by most accounts).   It was not that Sys III/V was bad, it was
> just unadorned and claiming it was cool and trying to give it a cool name
> was not going to make it cool.​
> Around this time we came up with the Universes hack, so you can have it
> both ways; but our kernel was more BSD that AT&T.
> As I said, funny, because a few years later with Stellar, the same group
> of people would >>start<< with a System V kernel and fold in BSD interfaces
> as needed.  We wrote our own FS (which was UFS-externally - i.e. BSD user
> api) but kernel insides completely new (extent based, more like VMS).
> We had decided that by then the AT&T code base was *cleaner to make scale
> on a multiprocessor*, as we had already lived the BSD MP nightmare once
> with the Masscomp kernel.     But the key was that even thought we used
> System V, we made darned sure the user mode API's (such as sockets, mmap,
> signals, namespaces etc) were the BSD APIs and that the BSD user code from
> UNIX and that VMS/FORTRAN sources would pretty much compile out of the box.
> We were at that point targeting Sun, Apollo & VMS customers so we knew it
> name meant nothing, it was all about how easy it was going to be for the
> code recompile and "just work".
> Back to the main point, AT&T Marketing was still chasing IBM at this
> time.  It was amazing to many of us watching the ship sink.   They really
> did not see where the future was and that they owned the SW technology that
> was going to dive it, but it was going to be sold to people other than whom
> IBM had traditionally sold.  They also made the fatal mistake of trying to
> grip it too tight and in doing so, it slipped through their fingers.
> Clem
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