Subject: Re: "pseudo messages" from ipop3d

From: lewst <[email-masked]>
Date: Wed, 15 Mar 2000 17:32:22 -0800 (PST)

Mark Crispin <[email-masked]> wrote:

> If you don't care about interoperability with the IMAP service, then perhaps
> some other POP3 server, such as Qualcomm's qpopper, is a better choice for
> you.

It's just too bad that the only reason I have to move away from
ipop3d is because the "pseudo message" shows up as a message in 
my mailbox.  This was a poor design decision.

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From: Yiorgos Adamopoulos <[email-masked]>
Date: Thu, 16 Mar 2000 20:12:05 +0200

> my mailbox.  This was a poor design decision.

You fail to understand, that for the UNIX MAILBOX FORMAT and interoperability 
with clients like elm, mutt, mail, mailx it is the only decision.
--
Yiorgos Adamopoulos, [email-masked]

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From: Vadim Zeitlin <[email-masked]>
Date: Fri, 17 Mar 2000 13:19:56 +0100 (CET)

> with clients like elm, mutt, mail, mailx it is the only decision.

 Sorry, but could you explain this (yet) a bit more? mail(x) doesn't
create nor uses such messages AFAIK, so how can this be possible?

 Thanks,
VZ

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From: Yiorgos Adamopoulos <[email-masked]>
Date: Fri, 17 Mar 2000 15:25:09 +0200

> create nor uses such messages AFAIK, so how can this be possible?

No it does not.  I had the same questions as you when I first started using 
imapd and ipop3d.  Since then I have seen Mark Crispin explaining the 
existence of this message when you use Unix mailboxes and imapd/ipop3d 
numerous times.

And there exists this very nice URL that explains it also:

	http://www.washington.edu/pine/faq/problems.html#xtocid1175429

Please read it.

As Mark explained previously in this very thread, this message is needed to 
calculate UIDs and is needed only when the messages are stored in the 
unix traditional mailbox (.mbox) format.  It is not bad design because we see 
it when not reading our email via imapd.

When this is the case two things happen:

- If you are using a mail reader that is compatible/developed with c-client 
then you do not see the message

- If you are using any other mail reader (such as mailx) then you see it.  
Plain and simple

If you decide not to use the .mbox format, and use .mbx for example, then the 
only way you can see your emails is via a client that knows of mbx (and mailx
is not one of them).

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From: Mark Crispin <[email-masked]>
Date: Fri, 17 Mar 2000 12:53:09 -0800 (PST)

OK, here's the current situation.

If I knew of a better way to do it than the pseudo-message, I would do it.
All the ways of doing it have problems.

We all know the problem with the pseudo-message.  It makes people send
complaints; and there's been enough complaints that I've been told to do
something about it.

The MD5 checksum trick is useless for IMAP.  Since it has to support IMAP,
doing the MD5 checksum trick would be that you'd have *both*, not either.

Putting the data in an auxillary file means a doubling of the number of files;
plus there is no guarantee that the user can necessarily create any other file
other than the INBOX; plus with shared folders it's likely that different
users would have different auxillary files and would end up stomping on each
other's UID base.

The only alternative solution that seems to be viable is to keep the data with
*EVERY* message in the mailbox (because any message can be deleted and lose
that data -- that's why the pseudo-message is kept apart and separate when you
use c-client software).  So, every time there's new mail, the next checkpoint
(mailbox close, check, or expunge) have to go and update that data in all the
messages.

So, the question is: do users hate the pseudo-message so much that they're
willing to have checkpoints do all those rewrites and be slower as a result?
I personally would have appreciate the big performance boost in imap-4.6, and
would rue having to give part of it up.  But I don't use traditional UNIX mbox
format.

I am still looking for better alternatives.  But if there is overwhelming
sentiment that the software is fast enough that you can tolerate a performance
loss to get rid of the pseudo-message, please let me know.  This issue with
the pseudo-message has been a major irritation for years now.

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From: Mark Crispin <[email-masked]>
Date: Fri, 17 Mar 2000 13:56:34 -0800 (PST)

On Fri, 17 Mar 2000 13:19:56 +0100 (CET), Vadim Zeitlin wrote:
> > You fail to understand, that for the UNIX MAILBOX FORMAT and
> > interoperability with clients like elm, mutt, mail, mailx it is the only
> > decision.

The answer to your specific question is:

mailx does not use UIDs.  However, there needs to be a way to prevent mailx
from damaging UID information.  The pseudo-message, *if* the user obeys the
instructions and does not delete it, serves that purpose.