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From: "Thomas Paulsen" <>
To: "Clem Cole" <>
Subject: Re: [TUHS] Additional groups and additional directory permissions
Date: Fri, 02 Aug 2019 21:00:12 +0200
Message-ID: <> (raw)
In-Reply-To: <>

isn't Kirk McKusic a member of our group? Guess he can contribute a lot on this issue.

--- Ursprüngliche Nachricht ---
Von: Clem Cole <>
Datum: 02.08.2019 15:28:18
An: Aharon Robbins <>, Doug McIlroy <>
Betreff: Re: [TUHS] Additional groups and additional directory permissions

> The best I can tell/remember is that groups went through 4 phases:
> 1.) No groups (earliest  UNIX) [ I personally never used this except in the
> V0 retrocomputing]
> 2.) First group implementation (Thompson) [My first UNIX introduction was
> with this implementation]
> 3.) PWB 1.0 (Mashey version) [then saw this post PWB]
> 4.) BSD 4.2 (wnj version) [and lived this transistion]
> Each was a little different in semantics.
> As Doug mentioned, many sites (like Research) really did not need much and
> groups were really not used that widely.   Thompson added something like
> the Project number of TOPS and some earlier systems.  Truth is, it did not
> help much IMO.   It was useful for grouping things like the binaries and
> keeping some more privileged programs from having to be setuid root.
> Mashey added features in PWB, primarily because of the RJE/Front end to the
> Mainframes and the need to have better protections/collections of certain
> items.   But they still were much more like the DEC PPN, were you were
> running as a single group (i.e. the tuple UID/GID).  This lasted a pretty
> long time, as it worked reasonably well for larger academic systems, where
> you had a user and were assigned a group, say for a course or class, you
> might be talking.  If you looked at big 4.1 BSN Vaxen like at Purdue/Penn
> State, *etc.*, that how they were admin'd.  But as Doug said, if you were
> still a small site, the use of groups was still pretty shallow.
> But, as part of the CSRG support for DARPA, there was a push from the
> community to have a list of groups that a user could be a part and you
> carried that list around in a more general manner.   The big sites, in
> particular, were pushing for this because they were using groups as a major
> feature.  wnj implemented same and it would go out widely in 4.2, although
> >>by memory<< that was in 4.1B or 4.1C first.   It's possible
> Robert Elz
> may have brought that to Bill with his quota changes, but frankly I've
> forgotten.   There was a lot of work being done to the FS at that point,
> much less Kirk's rewrite.
> But as UNIX went back to workstations, the need for a more general group
> system dropped away until the advent widely used distributed file systems
> like CMU's AFS and Sun's NFS.  Then the concept of a user being in more
> than one group became much more de rigeur even on a small machine.
> Clem

  reply index

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-01 12:35 [TUHS] Who's behind the UNIX filesystem permission Doug McIlroy
2019-08-01 16:22 ` John P. Linderman
2019-08-01 16:35   ` Arthur Krewat
2019-08-02  8:35   ` [TUHS] Additional groups and additional directory permissions arnold
2019-08-02 11:18     ` Tony Finch
2019-08-04  6:40       ` arnold
2019-08-02 12:45     ` Arthur Krewat
2019-08-02 13:06     ` Clem Cole
2019-08-02 13:28     ` Clem Cole
2019-08-02 19:00       ` Thomas Paulsen [this message]
2019-08-01 17:01 ` [TUHS] Who's behind the UNIX filesystem permission Nemo Nusquam
2019-08-01 18:26   ` Arthur Krewat
2019-08-01 20:14     ` Lyndon Nerenberg
2019-08-01 21:23 ` Dave Horsfall
2019-08-02 19:44 [TUHS] Additional groups and additional directory permissions Norman Wilson
2019-08-10  4:02 Kirk McKusick
2019-08-10  6:02 ` Thomas Paulsen

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