[TUHS] shared memory on Unix
rochkind at basepath.com
Thu Feb 2 05:24:36 AEST 2017
@Joerg: "Interesting.... does this mean that you did not do the rework that
defined the new ASCII based history file format?"
I'm sure it does, as I have no idea what that is/was. I stopped working on
SCCS around 1975 or 1976, about when the IEEE paper was presented.
On Wed, Feb 1, 2017 at 12:11 PM, Steve Johnson <scj at yaccman.com> wrote:
> I can't speak for the dates, but Ken did a hack to the OS to interface
> with his Chess machine. Recall that all the I/O on the PDP-11 was memory
> mapped, so as I recall he simply mapped a piece of kernel memory into user
> space. Was never privvy to the details.
> I do remember a conversation with Dennis about semaphores, though. He
> mentioned that no less than five groups inside of Bell Labs had hacked
> semaphores into the kernel. Each group did it differently. He thought
> they were all a bad idea -- his argument was, "what do you do if a process
> sets a semaphore and then dies? It's pretty clear that either releasing
> the semaphore or leaving it set would be catastrophic in some cases."
> (Of course there were other similar problems, such as a process closing
> its files and dying, and then the kernel discovering that the disc was
> full. Luckily, these days, the disc rarely gets full...)
> Also, a comment from my own experience with AT&T marketing. When I was
> responsible for the System V languages in Summit, I was told that a
> marketing group was staffed and that there was a person in charge of
> marketing the language products (at the time, C, Cfront (becoming C++),
> Fortran, Pascal, and Ada). I set up a monthly meeting with this person.
> The meetings went on for over a year, but *I never met with the same
> person twice!* It seemed that the only thing the marketing group knew
> how to do was reorganize the marketing group...
> At the time, a lot of people buying VAXes were running VMS because its
> FORTRAN was far better than UNIX F77 -- in particular, it had an
> optimizer. I started a project to build an optimizer for FORTRAN, and
> staffed it with several very good people. Every six weeks there would be
> an attempt to kill the project. Each time I'd repeat the argument for
> doing it, and it would be saved. We almost started to put these attempts
> to kill it on the calendar. At no time did I get any feedback, positive or
> negative, from AT&T marketing. When I left AT&T in early 1986, the
> optimizer, by now almost complete, was immediately killed again. I was
> later told by one of my former team members that it was revived several
> months later and finally made it out. And that the next year it was the
> best-selling add-on to System V.
> ----- Original Message -----
> arnold at skeeve.com
> <schily at schily.net>, <clemc at ccc.com>
> <tuhs at minnie.tuhs.org>
> Wed, 01 Feb 2017 11:33:05 -0700
> Re: [TUHS] shared memory on Unix
> Clem Cole <clemc at ccc.com> wrote:
> > Note that AT&T Marketing renames PWB 3.0 -- System III thinking that
> > "Programmer's Workbench" would be a bad name to sell against IBM, and
> > it the first non-research system for License outside of the the labs. If
> > you look at the documentation set, et al - it all says PWB 3.0 on the
> > and throughout Also, the BSD vs AT&T wars basically start around this
> > time....
> > Roll the clock forward and here is an new problem the PWB 4.0 moniker was
> > used internally, but AT&T marketing want to get rid of the PWB term - so
> > the decree comes down the next release is to be called System V.
> Sort of. I did some contract work for Southern Bell circa 1983. They
> were still part of the Bell System then. I worked on a PDP-11 running
> Unix 4.0. 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".
> 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.
> The doc I have describes UNIX as an operating system for the PDP-11,
> the VAX 11/780 *and* the IBM S/370 series of systems and the source
> code directory had the machine dependent bits for the IBM. Too bad
> that stuff never made it out.
> It's too bad that all I have is just the paper, but that's all I
> could get.
> That was a fun job, I learned a lot. Over lunch every day I read a few
> more pages of the manual, basically reading it from cover to cover
> by the time I was done. What a great way to learn the system!
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