Re: what is the benefit of imap? Another meta-question.
I think the best summary is that IMAP is a remote mailbox access
protocol, supporting all common mailbox operations at the protocol
level. POP is not: it supports full message retrieval, new-message scan
(kind of, via UIDL), and deletion. This makes it, at best, a queued
message pull protocol.
But as someone else said, IMAP is just more flexible. You may not need
all the features of IMAP, but since it fully encompasses everything that
POP supports, why not use it?
>> so the "leave mail on server" option that most pop-clients have is
>> certainly not a convenient way to access your mail remotely from different
>> locations.
If you have minimal needs, it works alright. It's implementation-
dependent since it's not done at the protocol level, but POP servers can
track basic message and mailbox status.
> Plus: POP needs locking, i.e. only one client at a time can access the
> mailbox which implies that tools should not perform time-consuming tasks
> while they have a POP session open.
That's implementation-dependent though. A server might require locking,
but it's not inherent to the protocol and it's possible to implement
one that has few of the contstraints that people have mentioned in this
thread. But historically, there are few really good POP servers, so
in practical terms you're not wrong.
Most of the things that people cite as flaws of POP are really flaws
in particular implementations, not in the protocol. The POP protocol
is limited in scope, but I don't think this is a flaw; POP just has a
different design goal.
(That said, it's really too bad that the POP and NNTP groups didn't
join forces from the start. With an NNTP server that supported
authentication and operationally understood the goals of user-oriented
mailbox access, it would have been a completely reasonable alternative
to both POP and IMAP, and much closer to IMAP in spirit.)
--
-D. dgc@xxxxxxxxxxxx NSIT University of Chicago
Just to clear the deck, I own no monkeys.