Re: [TUHS] Interesting commentary on Unix from Multicians.

[jnc@mercury.lcs.mit.edu (Noel Chiappa)]

    > From: Clem Cole

    > Not to put too fine a point on it, It seems like it would be fair to
    > say Multics was 'complete' by the time Organick published his book

This is a pretty ill-judged claim, IMO - but not for any particulars about
the Organick book, etc. The problem is more global.

When was UNIX 'complete' - when the first people were able to do real work on
the PDP-7? When non-programmer clerks from the patent group were able to use
the assembler UNIX on the PDP-11 to format parent documents? When it was
re-written in C for the 4th Edition (since the _portability_ of UNIX was IMO
perhaps the greatest factor in its eventual domination)? Etc, etc, etc.

The exact same problem applies to the question of 'when was Multics
'complete''.

    > don't know when it first appeared and can not seem to find it. ... I
    > bet I have the 3rd printing. ... Anyone have a first edition around
    > with the publication date?

The third printing _is_ the first edition. Anyway, it doesn't matter - see
above. And of course even if the book _wriring_ was finished at time T, it
wouldn't have been printed until some unknown time later. So that's really
pretty useless as a temporal marker; we have much better ones availablw.


    > From: Dan Cross

    > I can't see any indication that this is anything other than the first
    > printing.

My 3rd printing says 3rd was 1980, 2nd in 1976, and copyright 1972.

    > Organick's book is often said to describe an earlier version of the
    > system

Yes; I'm not sure if the version described in it was ever available for
general usege (which could be my definition of 'complete') - or even usage my
Multics system programmers. I don't remember all the details of the
differences (it's been way too long since I read it, and I don't know the
details of the 'first operational' Multics well enough), but for instance:

ISTR that it describes a version which had a linkage segment (holding
intermediate locations in outbound links - since segment >a>b>c might well
have different segment numbers assigned to it in the address spaces of
processes X and Y, so one copy of >a>b>c, shared between X and Y, couldn't
contain direct outbound links) _per segment_ (data or code) - but operational
Multics (I don't know if this is from 'first available to users', or 'first
available to Multics system programmers', or what) collapsed all the linkage
info into a 'combined linkage segment', in which the linkage info from all
the segments in a process' address space were combined (by copying) into a
single linkage segment.

Etc, etc, etc.

    > I understand that Multics got much better after the move to the 6180

I'm not sure that the 6180 made that big a difference to the environment the
average use saw. My understanding (not having been there) was that the big
_architectural_ difference was that cross-ring inter-segment references were
done and monitored in hardware, so a host of security holes caused by
insufficient checking of cross-ring inter-segment pointers were caught
automatically. (The 6180 was also built out of SSI chips, unlike the 645 which
was individual transistors, like a KA10.)

	Noel