Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ames!amdahl!pyramid!octopus!vsi1!altnet!uunet!mcvax!ukc!etive!jpd
From: jpd@etive.ed.ac.uk (Paul Dourish)
Newsgroups: comp.mail.misc
Subject: Re: central mail server
Keywords: mail NFS
Message-ID: <844@etive.ed.ac.uk>
Date: 14 Oct 88 15:42:07 GMT
References: <363@asuvax.UUCP> <464@Terra.cc.brunel.ac.uk> <9449@swan.ulowell.edu> <1431@xyzzy.UUCP> <226@ists>
Reply-To: jpd@etive.ed.ac.uk (Paul Dourish)
Organization: Concurrent Supercomputer Project, EUCS, Edinburgh University
Lines: 26

In article <226@ists> mike@ists (Mike Clarkson) writes:
>In article <1431@xyzzy.UUCP>, meissner@xyzzy.UUCP (Usenet Administration) writes:
>> When some mail agent [...] wants to modify the mailbox for
>> a user "joe", it creates a file in the spool directory with ".lock"
>> tacked on [...] with options to open to fail if the
>> file exists.
>
>NFS supported file-locking with the lockd daemon (usually :-).
>The problem is that /bin/mail had to be rewritten to to use the
>new calls to the network locking.  This was done in 4.0, and at the
>same time, the lockd bugs were alledgedly squashed.

Actually, "correct" mailbox locking predates this -- 4.3BSD introduced a
version of /bin/mail which actually used flock() to lock the mailbox. Imagine
my surprise when I ported my mail user agent away from a 4.3BSD VAX and
discovered that the mailbox locking didn't work in other places!

Since 4.3, the flock() (or equivalent) call in other systems has filtered
through slowly. I'm surprised it took until 4.0 to reach SunOS.

--
Paul Dourish,                           JANET: jpd@uk.ac.ed.itspna
Concurrent Supercomputer Project,       ARPA: jpd%ed.itspna@nss.cs.ucl.ac.uk
Edinburgh University Computing Service  UUCP: ...!uunet!mcvax!ukc!itspna!jpd

         "Ain't they got no barbers where you come from, boy?"