/usr/spool/mail/:saved

[Carl S. Gutekunst]

In article <278 at massey.ac.nz> K.Spagnolo at massey.ac.nz (Ken Spagnolo) writes:
>Does anyone know what this directory is for?  Ours has never even been
>modified (9815 OSx4.4).

It *used* to be for att mail(1) and mailx(1), which shuffled and copied your
mailbox in and out of this directory in an attempt to prevent damage to the
file in the event of a system crash while the mailbox was being written back.
If mail(1) found a mailbox in the :saved directory, it would assume the system
had crashed since the last time you received mail, and recover it for you.

This feature, although possibly useful, was removed in OSx 4.1 whan the SVR3
mailx was ported and modified to use 4.3BSD-style flock(2) file locking. This
was one of those difficult choices that we face in getting the OSx dualport
to work properly: should we modify 4.3BSD Mail to use the old lockfile mecha-
nism, or modify SVR3 mailx to use flock(2)? In the end, 4.3BSD won, since it
was both easier to code and more robust. But it did make the :saved mechanism
impossible, since it relied on being able to lock a file that hadn't been
created yet, and you can't do that with flock(2).

<csg>