The Unix Heritage Society mailing list
 help / color / mirror / Atom feed
From: segaloco via TUHS <>
To: Jonathan Gray <>
Subject: [TUHS] Re: Early supported UNIX manual
Date: Sat, 24 Dec 2022 08:58:06 +0000	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

Your reference to sema(2) in CB-UNIX prompted me to go check the source and curiously, that isn't in sysent.c: (p. 50).  However, there is a sys5.c with some semaphore stuff in it.  Not how the code gets from the sigcall entry to that file, maybe there's a CB-specific syscall aggregator like the sys3b systemcall for 3B20-specific stuff.  It had never actually occurred to me that the semaphores in SVR1 weren't the ones from CB-UNIX, I thought they just forklifted all the IPC into 4.0 from CB.  That then means the semaphores that carried through in System V originated at least in UNIX/TS 4.0, but not by way of CB.  Minor trivia, but that's news to me.  Maybe the sysV modification request logs can shed some light, I remember seeing several IPC mentions in there.

- Matt G.

------- Original Message -------
On Friday, December 23rd, 2022 at 7:30 PM, Jonathan Gray <> wrote:

> On Thu, Dec 22, 2022 at 04:44:32PM -0500, Phil Budne wrote:
> > Matt G wrote:
> > 
> > > One area of immediate curiosity for me is the init system, whether the pages suggest it is more in line with research (rc and ttys files) or TS (inittab, runlevels).
> > 
> > The init (VII) page mentions /etc/rc and refers to ttys (V) which says the file
> > consists of lines with three characters (enable, tty name, getty arg)
> > 
> > getty (VII) describes behaviors for 0, -, 1, 2
> > 
> > The one interesting bit in section (II) is lock (system call 62.) that
> > implements semaphores with subfunctions lock/unlock/tlock, all of
> > which take a non-negative semaphore ID called a flag.
> used by MERT:
> Programmer Manual - UPM - White Tabs/System Calls - man2/lock.2.pdf
> "The semaphores provided in the MERT/UNIX supervisor are identical to
> those provided by the USG-UNIX Generic 3 system [8].
> [8] Brandt, R. B., Implementation of Semaphores and Messages in UNIX, MF-76-8234-076."
> "Make (a program for maintaining other programs) was launched at the
> CSRC towards the end of the year and was immediately adopted by USG for
> the next generic release (PG-1C300 issue 2). This was a snapshot of the
> USG system at mod level 3.33 (January 1976) indicating at least three
> distinct levels of evolution: the generic releases, major and minor USG
> mod levels."
> "Generic 3.0 was released in spring 1977 (delayed from January)."
> Pirzada, A Statistical Examination of The Evolution of the UNIX System
> "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."
> Steve Johnson
> In CB-UNIX there was sema(2):
> In System V Release 1, semctl(2), semget(2), semop(2)
> xenix creatsem(2), opensem(2), sigsem(2), waitsem(2)

  reply	other threads:[~2022-12-24  8:58 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-22 18:52 [TUHS] " Phil Budne
2022-12-22 19:51 ` [TUHS] " segaloco via TUHS
2022-12-22 21:44   ` Phil Budne
2022-12-22 21:55     ` segaloco via TUHS
2022-12-24  3:30     ` Jonathan Gray
2022-12-24  8:58       ` segaloco via TUHS [this message]
2022-12-24 10:30         ` Jonathan Gray
2022-12-23  8:47 ` [TUHS] Re: Book Scanning. (Was: Early supported UNIX manual) Ralph Corderoy
2022-12-23  2:26 [TUHS] Re: Early supported UNIX manual Noel Chiappa
2022-12-23  4:32 ` Phil Budne
2022-12-23  7:52   ` arnold
2022-12-23  9:09   ` Jonathan Gray
2022-12-23 18:04     ` Phil Budne

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='' \ \ \ \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).