House of the rising Moonglum

So, one of my biggest complaints about tiger is that the mail app included with it moved away from the standard mbox format to some file based proprietary format. (Many simple intros to e-mail protocols and formats can be found on about.com.) This pissed me off because the mbox format is nice and standard and will not disappear any time soon. E.g. my mail is safe even if Apple mail disappears. Well, as I eventually discovered with mail 1.0, mail 2.0 also uses a standard.

Rather than using the mbox standard Mail has switched to the newer maildir file format. Rather than using one file per mailbox like mbox, it uses one file per message and uses folders as mailboxes. Maildir was invented for qmail which is an IMAP server that has been around for a while. Basically, the fact that multiple clients can hit the same mbox once you have IMAP led to locking issues which would corrupt the mbox file and make you lose mail. Of course they make maildir look like the great savior, but it just shoves the hard work from the mail clients and servers onto the file system. WU-IMAP makes strong arguments for the older flat file based systems, in particular they are concerned with file thrashing during certain operations. Another MTA producer actually did a study of the different modalities of mail use in a flat file system and a file based system. They both had advantages and disadvantages, but the big disadvantage of the file based system was searching. Of course since Apple Mail uses spotlight to search that problem goes away.

Some other advantages are the fact that if one mail file gets corrupted it doesn’t kill the entire mailbox. The messages themselves become more human readable. The disadvantages are basically that for archival purposes it just sucks. I have like 100,000 messages in my archive. Backing that up will suck. Really suck. Of course I can just gzip it up and then it is one file again.

Mostly I am just happy that they actually went from one file format standard to another. That makes me very happy. I feel much better about upgrading now. Which I still haven’t done. Dude, it’s been like a whole week!

(Another disadvantage is that I guess moving to a different format introduced a number of bugs that they had gotten rid of in the old version. *sigh*)