> From: "Ron Natalie"
> At some point .. and the ability to assign/pass structures got
> supported, though I thought that was the compiler that came with V7.
That is my vague recollection too.
> I'm still annoyed they didn't fix arrays when they fixed structs.
Which aspect? The ability to assign/pass/return arrays, or the funky way that
array naming worked (I'm trying to remember the details, I think it was
something to do with 'arrays' passed as arguments - it was actually a pointer
that was passed, but the declaration didn't have to say 'pointer').
Noel
> From: Tony Finch
> when did C get its cast operator?
Well after that piece of code was written! :-)
I don't recall exactly off the top of my head, but I recall 2-3 notes to
users about the evolution of C post 'vanilla' V6; I think a lot of it was
related to work being done on typetting stuff, hence the moniker
'phototypsetter compiler' which was applied to that 'improved' C.
One of the notes is fairly common, but another I have only in hardcopy
(although I scanned it at one point).
I'll try and turn all of them, along with some notes I made about the
differences between 'vanilla' V6 C and 'phototypsetter C' (which a lot of the
later V6 users started with - I certainly did), into an article on the
Computer History wiki on the early evolution of C.
Noel
PS:
> I recall 2-3 notes to users about the evolution of C post 'vanilla' V6
> ...
> One of the notes is fairly common, but another I have only in hardcopy
> (although I scanned it at one point).
More here:
http://minnie.tuhs.org/pipermail/tuhs/2014-October/005218.html
If anyone knows of any other documentation of C evolution, I'd be interested
in hearing about it for the Computer History wiki page.
Noel
> From: "Steve Johnson"
> The number on the left is a PDP-11 address, probably for some kind of
> control register.
It's the Processor Status Word, which contained the CPU's hardware priority
level, condition codes, etc.
> That's a construction that's left over from B.
I wonder why it was written as "0177776->integ", rather than "*017776"?
Probably the former allowed the C compiler to work out what size the operand
was. (BTW, 'integ' was declared in a structure declaration as follows:
struct {
int integ;
};
(Did the code looked at actually say "0177776->int"? The compiler might have
barfed on a reserved keyword being used like that.)
Noel
Has anyone got a setup where they can run something like nm(1) on the
compiled Third Edition Unix C files and send me the output?
(Alternatively, just send me the .o files, and I'll whip up something to
read their symbols.) I tried to compile the source code on a modern
system by hacking old C to something closer to what GCC will accept,
with commands such as the following.
cc -E dp.c |
sed 's/=\([&|+-]\)/\1=/g;s/struct[ \t]*(/struct {/' |
gcc -w -x c -
However, I stumbled on the use of structure fields on things that aren't
structures, e.g. "0177776->int =| 300"
It has often been told how the Bell Labs law department became the
first non-research department to use Unix, displacing a newly acquired
stand-alone word-processing system that fell short of the department's
hopes because it couldn't number the lines on patent applications,
as USPTO required. When Joe Ossanna heard of this, he told them about
roff and promised to give it line-numbering capability the next day.
They tried it and were hooked. Patent secretaries became remote
members of the fellowship of the Unix lab. In due time the law
department got its own machine.
Less well known is how Unix made it into the head office of AT&T. It
seems that the CEO, Charlie Brown, did not like to be seen wearing
glasses when he read speeches. Somehow his PR assistant learned of
the CAT phototypesetter in the Unix lab and asked whether it might be
possible to use it to produce scripts in large type. Of course it was.
As connections to the top never hurt, the CEO's office was welcomed
as another ouside user. The cost--occasionally having to develop film
for the final copy of a speech--was not onerous.
Having teethed on speeches, the head office realized that Unix could
also be useful for things that didn't need phototypesetting. Other
documents began to accumulate in their directory. By the time we became
aware of it, the hoard came to include minutes of AT&T board meetings.
It didn't seem like a very good idea for us to be keeping records from
the inner sanctum of the corporation on a computer where most everybody
had super-user privileges. A call to the PR guy convinced him of the
wisdom of keeping such things on their own premises. And so the CEO's
office bought a Unix system.
Just as one hears of cars chosen for their cupholders, so were these
users converted to Unix for trivial reasons: line numbers and vanity.
Doug
All, I'm writing a paper based on my June 2016 talk on PDP-7 Unix. As part
of that I was looking at the BCPL -> B -> NB -> C history. And as part of
that, I was reading Ken's B manual, written in 1972:
https://www.bell-labs.com/usr/dmr/www/kbman.pdf
Then I noticed at the end Ken refers to:
Ritchie, D.M. The UNIX Time Sharing System. MM 71-1273-4.
which makes me think that the draft version Doug McIlroy found
(now at http://www.tuhs.org/Archive/PDP-11/Distributions/research/McIlroy_v0/UnixEd…)
must have made it into a full memorandum.
Given that we have the memorandum number, does anybody know if it
would be possible to find it in the archives from what was Bell Labs?
Cheers, Warren
J.F.Ossanna was given unto us in 1928; a prolific programmer, he not only
had a hand in developing Unix but also gave us the ROFF series.
PS: Ada Lovelace, arguably the world's first computer programmer, was
given unto us in 1815; she saw the potential in Charles Babbage's
new-fangled thing.
--
Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."
On Thu, Dec 8, 2016 at 5:39 AM, Joerg Schilling <schily(a)schily.net> wrote:
> Back to the Bourne Shell:
>
> The original Bourne Shell did not use malloc, but rather had a SIGSEGV
> handler
> that used to extend the "string stack" called "stak" via sbrk() whenever
> the
> code tried to access data beyond the end ot the heap.
>
Right although the 68K was not the first or the only system to have that
problem - again IIRC Series/1 and maybe one of the PE systems. You are
correct then SunOS and >>some<< of the 68000 based system did have the
problem you suggested. And in fact, Masscomp (and Apollo) which used
68000's (but used two of them so could run full VM) could survive that
style of fault (because it never occurred).
BTW: the "conceptual problem" , you mentioned while true, is being a little
harsh. As the one of the 68K designers (Les Crudele) said to me once,
when they wrote the microcode, there were not thinking about instruction
restart - so the issue was that Nick did not save enough state to do it.
The model for the 68000 that they were using was the base/limit PDP-11 and
the original PDP-10. Also at the time, the competition was the 6800, the
8080, Z80, 6502. They were trying to put a PDP-11/70 on chip (without
getting into trouble like CalData did - which Les, Nick and team were very
aware having been DEC and CalData customers before they were at Moto].
While we think of the 68000 family has being 32 bit, the fact is inside it
is a 16 bit system (the barrel shifter and execution functions are 16).
And it was a skunk works project -- the 6809 was Moto's real processor.
It was an experiment done by a couple of rogue engineers that said - hey we
can do better, The fact was they made a chip that was good enough to
actually compete with the Vax in the end, because it was fast enough AND
they had the wisdom to define 32 bits of address space and 32 bit
operations (again having been PDP-11 users), but as Les used to say - part
of the thinking was that while DEC was moving to the Vax, they had hoped to
break into the area that they 16 bits minis claimed - which they in-fact
did.
And if you think in terms of a Clay Christensen's disruption theory, the
fact that VM did not work easily (i.e. was a "worse" technology than the
Vax) was ok - a new breed of customer did not care. 68000 was huge
success, despite Moto marketing ;-)
To me the larger issue with the 68010 was that when Nick did add the
restart microcode, the new '10 microcode actually dumped version dependant
state on the external stack (in Intel terminology -different "step" '10 put
different state on the external stack or worse, could not restart an
instruction that had been saved from a different step processor).
This screw up was a huge issue when we did replaced the "executor" with a
68010, because it meant that all cpu boards had to be the same processor
microcode revision. Masscomp was of course the first to make an MP, so was
the the first firm to run into the issue (I remember debugging it - we
could not reproduce the issue because of course tjt and my own machine's by
chance had "MPU" boards as we called them with the same step -- it was one
of the field service guys that realized that the customer system had a
mixed step board -- i.e. when they replaced a single MPU in the field, the
system stopped working). IIRC: Moto never fixed the '10, as that
processor was reasonably short lived in the open market. They did fix the
microcode in the '20 so the state on the external stack was independent of
stepping.
Clem
