From: mascheck@in-ulm.de (Sven Mascheck)
Subject: [TUHS] environments/universes (was: Unix v6 problem with /tmp)
Date: Fri, 29 Jul 2016 01:16:39 +0200 [thread overview]
Message-ID: <20160728231639.GA299581@lisa.in-ulm.de> (raw)
In-Reply-To: <CAC20D2NymVJ=fxcwBUk3ObU_iwc+FieOXLpnt-d=PJwJuzdAeg@mail.gmail.com>
On Wed, Jul 27, 2016 at 04:57:47PM -0400, Clem Cole wrote:
> I created Conditionally Dependant Symlinks (CDSL) which I think only showed
> up in Masscomp's RTU, Stellix and Tru64. The were not only late binding,
> but added the concept of a user settable context. Very handy when trying
> to create a "single system image" from multiple system.
How did you implement it?
> Also, around the same time that Dennis added symlinks, Apollo's Aegis (aka
> Domain) guys came up with a cool idea where you can run application code
> from a link - extensible types. I remember talking to Dennis and Ken
> about them at a SOSP IIRC, and toyed with putting them into one of the
> Locus UNIX Kernels. We proposed it for HP-UX and Tru64, but never got
> funded to try it, although I think / believe others did some where else.
I just wonder if and how the following are related to the above two.
Sequent Dynix "universes" (idea picked up by Siemens Sinix) puts several
targets in one symlink. Example:
ln -c ucb=.bin att=/usr/att/bin /bin
and the actual resolving (and usage of different default PATHs)
is controlled by an environment variable, as far as I know
(s.a. http://www.in-ulm.de/~mascheck/various/universes/)
HP-UX 9 "context dependent files" (as early alternative to NFS) make use of
the set uid bit on directories and work like this,
# mkdir /etc/inittab
# chmod +H /etc/inittab
# touch /etc/inittab+/node1 /etc/inittab+/default
By accessing /etc/inittab, node1 will see the file node1, other systems
will see default (s.a. http://www.in-ulm.de/~mascheck/various/permissions/)
> [...]
> You are right the BSD 4.2 made the world know about them but like
> a number of things in BSD (such as networking) it was in some
> cases a (better) integration of ideas others had played with before.
F.i. #! also got widely known in 4.2BSD but was suggested by DMR before 8th ed.
-Sven
next prev parent reply other threads:[~2016-07-28 23:16 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-27 20:28 [TUHS] Unix v6 problem with /tmp Mark Longridge
2016-07-27 20:31 ` William Pechter
2016-07-27 20:57 ` Clem Cole
2016-07-27 21:01 ` Clem Cole
2016-07-27 21:10 ` William Pechter
2016-07-28 0:49 ` Clem cole
2016-07-28 1:03 ` William Pechter
2016-07-28 11:23 ` [TUHS] History repeating itself (was: Unix v6 problem with /tmp) Michael Kjörling
2016-07-28 12:18 ` Tony Finch
2016-07-28 13:57 ` John Cowan
2016-07-30 7:56 ` Greg 'groggy' Lehey
2016-07-30 11:41 ` William Cheswick
2016-07-30 23:28 ` Greg 'groggy' Lehey
2016-07-30 23:50 ` scj
2016-08-01 11:36 ` Tony Finch
2016-07-30 14:15 ` John Cowan
2016-07-30 15:30 ` [TUHS] History repeating itself Michael Kjörling
2016-07-28 1:03 ` [TUHS] Unix v6 problem with /tmp Clem cole
2016-07-28 23:16 ` Sven Mascheck [this message]
2016-07-29 3:05 ` [TUHS] environments/universes (was: Unix v6 problem with /tmp) arnold
2016-07-29 14:14 ` Clem Cole
2016-07-29 13:55 ` Clem Cole
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