On Thursday 16 December 2004 04:32 pm, Andreas Aardal Hanssen wrote: > On Thu, 16 Dec 2004, Jeremy Kitchen wrote: > >just curious, but why is binc trying to lock the mailbox? isn't the > > maildir format supposed to eliminate the need for locking?
> Good question. Actually the answer is that yes, Maildir was designed so no
> locking would be needed. And yes, Binc IMAP locks the maildir... The
> reason is that Dr. Bernstein, who designed this mailbox format, only had
> qmail-pop3d and qmail-local in mind (and, quite frankly, it was designed
> for mailboxes with few messages also). For both these apps, no locking is
> required. Unfortunately, IMAP4 has other requirements when assigning
> unique identifiers to each message that force us to use the lock after
> all.
>
> In the POP3 protocol, the unique name of a message qualifies as a UID. So
> no matter what messages come and go and it what order, POP3 can just look
> at Maildir messages' file names. Clients can sync their local storage with
> the POP3 server by comparing the UIDs it advertises, disregarding their
> textual format.
>
> In IMAP, the unique identifiers are assigned in strictly ascending order
> on a per mailbox basis, starting at a fixed number (like 1) and increasing
> one after one. So the first message seen by the IMAP server gets the UID
> 1. The next gets UID 2. A message can then only get UID 4 if the server
> has first announced the arrival and then the expunge of UID 3. These UID
> numbers are unique for a message, and shared among all concurrent clients.
that's an unfortunate design flaw in IMAP. I feel bad that you have to deal
with such madness :)
> Hope this answers your question.
yes, it does, thank you :)
Sorry if I sounded like I was trying to be critical, I figured there was some
reason for it, and I was just curious. :)
-Jeremy
--
Jeremy Kitchen ++ Systems Administrator ++ Inter7 Internet Technologies, Inc.
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