[TUHS] origin of null-terminated strings

[Tom Perrine]

I can offer at least one perspective on Multics, although from a
limited viewpoint.

I was an Explorer Scout at post 414, sponsored by Honeywell, in Phoenix,
from about 1972 onwards. This was a "high tech" special interest Post, and
our interest was computers - no surprise.

Weekly meetings included time using Teletypes (and later nicer terminals)
to connect to a GCOS system in Phoenix. Programming in Basic, FORTRAN,
COBOL and other arcane languages ensued. As did "an incident". Pretty
minor, but yeah, some high school kids "popped" (for some value of
"popped") the local GCOS system and got access to some files they shouldn't
have. I'm not sure if this was dumpster diving, or a real bug, or just
exploiting some employee carelessly setting file permissions to "read and
write for the entire system". I strongly suspect the latter.

As a result, all our GCOS accounts were cancelled and we were moved to
System M, one of the primary development systems for Multics. As was new
and not all common at the time, the entire source code for the entire
system was available online - and not just because this was a dev system,
this was the norm for all Multics owners. In this way, Multics followed the
UNIX model, or maybe they came from a common theme.

The Post took to PL/1 in a big way and delivered some interesting changes
to (mostly) the games on the system - vbg (Video BackGammon), chess, yet
another space wars clone, and a huge expanded ADVENTURE. There was also
some interesting new programming, including finding a way to exploit IPC
channels, and another way to crash the front end processor, that led to
some emergency bugfixes being rolled out (I later learned) overnight to the
Pentagon and "the Fort" customers.

Speaking of which, there was a bit of a kerfluffle when someone who shall
remain nameless, innocently asked "I identified all the Multics systems in
the site documents, except System N. Where is System N?" in a public forum
on System M. I was warned Never To Speak of System "N" Ever Again Or Else.

Over the next 10 years, a lot of my technical life was around Multic. As a
Boy Scout, and eventually as a student intern at Honeywell. Throughout
college all my engineering programming was done on Multics, mostly in pl1,
instead of fortran. As an intern I worked on projects across the GCOS
(GCOS-8), Multics and even a little CP-6 spaces. I got to see and hear how
different parts of the company saw the GCOS vs Multics conflict, admittedly
filtered through the eyes of a still naive intern. Here are some
recollections and talking points.


   1. Multics hardware is too expensive!
      1. GCOS 8 HW, which would have run Multics, GCOS classic and the
      someday GCOS 8 was even more expensive)
      2. Multics HW was expensive because they built and burned-in an
      entire GCOS system, and then partially took it apart, re-wired the CPU
      boards and other parts, and then put it back together!A Multics CPU had
      some boards in common with a GCOS CPU, some were modified
boards, and some
      were completely separate, if I recall correctly. Wirewrap CPU boards in
      addition to the wirewrapped backplane, which was also (I think) a
      built-and-then-rewired GCOS backplane.
   2. Our customers want more batch and less timesharing! - Multics doesn't
   have a real batch mode!
      1. which could have easily been addressed with a "dusty deck
      translator" from GCOS JCL to Multics "absentee" scripts.
   3. Timesharing is a fad and too expensive - look at how few people  our
   GCOS customers put on TSS!
      1. yeah, because GCOS TSS was an afterthought - a big pasted-on batch
      job that remained primitive compared to Multics and other competitors -
      looking at you TOPS-20, which was also up and coming
   4.  Our profit margins on GCOS SW and HW are better - so we should sell
   more GCOS!
   5. Spending money on Multics will take away resources from our bread and
   butter GCOS, which is where we make money!
   6. No one cares about PL/1 - all our customers want COBOL and FORTRAN
      1. which Multics had, and a better COBOL compiler than GCOS - I
      learned COBOL68 and COBOL74 on both - and along the way found a bug that
      would crash THE ENTIRE GCOS OPERATING SYSTEM (not just the compiler!) if
      you mis-spelled "ENVIRONMENT DIVISION" in a COBOL74 program.
   7. GCOS (formerly GECOS, thankyouverymuch) is the real legacy of GE, not
   that research project from MIT!!! - Multics is a toy we were paid to make,
   that will never make a dime!
   8. There was some rivalry between Phoenix and Billerica(?) that was
   mostly kept away from "the kids", so we didn't see that in detail but it
   was there.
   9. This rivalry seemed to be (in retrospect) two orgs fighting over
   ever-scarcer resources as the mini/super-mini revolution came on strong. A
   Multics CPU was pretty much a synchronous 1 MIP machine (per CPU). Of
   course you could have up to 8(?) CPUs and the I/O bandwidth was light years
   ahead of the super-minis, but DEC said that the VaX-11/780 was a "1 MIP
   machine" and it was cheaper than a mainframe, so there!!

Anything else would probably be off topic for TUHS, but with the
inter-twined DNA of Multics and UNIX, perhaps this is actually on-topic?

I would point out that I don't think Multics was a victim of UNIX adoption,
as that (from my dim recollection) took place years after Multics dev had
been mostly capped.

After Multics, my first UNIX system was PWB on a PDP-11. It was quite the
change, but led to the rest of my career - BSD, KSOS, SysV, IRIX, Ultrix,
SunOS, Solaris, UNICOS, others and eventually Linux.

You never forget your first :-)

Regards,
--tep




On Sat, Dec 17, 2022 at 10:17 AM Tom Lyon <pugs78 at gmail.com> wrote:

> Clem doesn't mention CP-67/CMS, which IBM kept trying to kill in favor of
> CMS.
> From Melinda Varian's amazing history of VM, I gleaned these factoids:
> CP-67 - 8 sites by May '68
> Feb of 68 - IBM decommits from TSS
> Apr 69 - IBM rescinds decommit of TSS
> CP-67 - 44 sites by 1970, ~10 internal to IBM
> May 71 - TSS finally decommitted
>
> So TSS was a rocky road, while CP&VM were simple and just worked.
>
>
>
> On Sat, Dec 17, 2022 at 9:13 AM Clem Cole <clemc at ccc.com> wrote:
>
>> Given the number of ex-MTS (Bill Joy and Ted Kowalski, to name two) and
>> TSS hackers that were also later to be UNIX hackers after their original
>> introduction to system programming as undergrads.  I will keep this reply
>> in TUHS, although it could be argued that it belongs in COFF.
>>
>> Note good sources for even more of the background of the history politics
>> at both IBM & GE can be found in Haigh and Ceruzzi's book: "A New
>> History of Modern Computing
>> <https://www.amazon.com/New-History-Modern-Computing/dp/0262542900>" -
>> which I have previously mentioned as it is a beautiful read.
>>
>> On Fri, Dec 16, 2022 at 5:27 PM Douglas McIlroy <
>> douglas.mcilroy at dartmouth.edu> wrote:
>>
>>> IBM revealed Gerrit Blaauw's skunk-works project, the 360/67,
>>> but by then the die had been cast. Michigan bought one and built a
>>> nice time-sharing system that was running well before Multics.
>>>
>> All true, but a few details are glossed over, and thus, this could be
>> misinterpreted - so I'm going to add those as one of the people.
>>
>> TSS and the /67 was IBM's answer to Multics, as Doug mentions.  Note that
>> the /67 could run as a model /65, which as I understand it, most of the
>> ones IBM sold did.
>>
>> At the time, IBM offered the /67 to Universities at a
>> substantial discount (I believe even less than the /65).  Thus, several
>> schools bought them with Michigan, CMU, Cornell, and Princeton that I am
>> aware of; but I suspect there were others.
>>
>> TSS was late, and the first releases could have been more stable.
>>  Cornell and Princeton chose to run their systems as /65 using the original
>> IBM OS.  CMU and Michigan both received copies of TSS with their systems.
>>  Michigan would do a substantial rewrite, which was different enough that
>> became the new system MTS.   CMU did a great deal of bug fixing, which went
>> back to IBM, and they chose to run TSS.  [I believe that CMU runs OS/360 by
>> data and TSS at night until they felt they could trust it to not crash].
>> Nominally, TSS and MTS should share programs, and with some work, both
>> could import source programs from OS/360 [My first paid programming job was
>> helping to rewrite York/APL from OS/360 to run on TSS].  So the compilers
>> and many tools for all three were common.
>>
>> MTS and TSS used the same file system structure, or it was close enough
>> that tools were shared.  I don't know if OS/360 could read TSS disk packs -
>> I would have suspected, although the common media of the day was 1/2" mag
>> tape.
>>
>> This leads to a UNIX legacy that ...  Ted's fsck(8) - which purists know
>> as a different name in the first version -  was modeled after the disk
>> scavenger program from TSS and MTS.   icheck/ncheck et al. seem pretty
>> primitive if you had used to see the other as a system programmer first.
>>  Also, a big reason why all the errors were originally in uppercase was the
>> IBM program had done it.  In many ways, neither Ted nor I knew any better
>> at the time.
>>
>> Clem
>>
>>
>>
>>
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