-Some vendors, in a misguided attempt to solve the security problems of
-/usr/spool/mail, have made all MUAs (e.g., /usr/ucb/Mail) setgid mail.
-After you get rid of /usr/spool/mail, you can also disable those
-setgid-mail bits.
-
-
-2. The trouble with mbox
-
-The mbox format---the format of ~user/Mailbox, understood by BSD Mail
-and lots of other MUAs---is inherently unreliable.
-
-Think about it: what happens if the system crashes while a program is
-appending a new message to ~user/Mailbox? The message will be truncated.
-Even worse, if it was truncated in the middle of a line, it will end up
-being merged with the next message! Sure, the mailer understands that it
-wasn't successful, so it'll try delivering the message again later, but
-it can't fix your corrupted mbox.
-
-Other formats, such as mh folders, are just as unreliable.
-
-qmail supports maildir, a crashproof format for incoming mail messages.
-maildir is fast and easy for MUAs to use. Even better, maildir works
-wonders over NFS---see below.
-
-I don't want to cram maildir down people's throats, so it's not the
-default. Nevertheless, I encourage you to start asking for maildir
-versions of your favorite MUAs, and to switch over to maildir as soon as
-you can.
-
-WARNING: qmail uses flock() to lock ~user/Mailbox. This agrees with the
-modern mail.local locking choice. If your MUA doesn't use flock(), your
-best bet is to switch to maildir, and to set up synchronous maildir2mbox
-execution, as described below.