> 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
So this is weird. My publisher contacted me this week asking for permission
to send a copy of my book to these folks: https://archiveprogram.github.com/
Hadn't heard of them before. Looks like they're filling their archive with
stuff from github which means that most of the stuff being preserved by TUHS
is likely not there. Might be a good idea to see if it can be included. I
have no contact with these folks but can probably get a contact from my
publisher if this is something that y'all think is worth doing.
Jon
> Does {Reiser's bitblt replacement] exist for the rest of us to study?
A not-very-thorough search at tuhs turned up V9/jerq/src/lib/j/bitblt.c
It appears to be a pre-Reiser bitblt, not what was asked for. But
weighing in at over 800 lines of C, it vivifies the challenge that
Reiser met in half the space.
Doug
The recent discussion about Research choosing BSD's paging over
Reiser-London's brought to mind a stunning program by Reiser that
Research did adopt.
A critical primitive in the Blit terminal was bitblt (block transfer
of a rectangular area). It was used ubiquitously, for example to
refresh data when window-stacking changed, to move data within a
window, or to pop up a menu.. The display memory was word-oriented, so
bitblt was fraught with niggling details about bit alignment and
overlap of source and destination. A general bitblt subroutine was a
rats' nest of conditionals--grossly inefficient for important special
cases like scrolling.
Bitblt got refined (i.e. elaborated) several times before Reiser did
away with it entirely. Instead he wrote a just-in-time generator of
optimal code. Thousands of distinct variants, which varied in size
from 16 to 72 bytes, could be produced by the same 400 lines of
assembler code.
Doug
