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Re: Definition of "folder"

1998-09-28 16:46:16
On 28 September 1998, era eriksson <era(_at_)iki(_dot_)fi> wrote:
On Mon, 28 Sep 1998 13:41:28 +0300 (EET DST), I wrote:
[...]
 > <contest>
 >   <task>

Reassigned: Look at what I have now and think of ways to improve it.
(See below.)

Open questions in Appendix A (MX hosts etc) include:

  * Anything I misunderstood or formulate too vaguely?
[...] 

    Ok, here's my shot.

:  Berkeley mbox format
:         This is a flat file, with no explicit message delimiter in the
:         classical sense. Each line starting with the five characters
:         "From " and preceded by either an empty line or beginning of
:         file is the beginning of a new message.
:         Some exciting more or less incompatible variants of this format
:         exist.

   Berkeley mbox format
          This is a flat file, with no explicit message delimiter in the
          classical sense.  Each line starting with the five characters
          "From " and preceded by either an empty line or beginning of
          file.  Some exciting more or less incompatible variants of
          this format exist, however the one used by sendmail is by far
          the most common these days.

:  MH format
:         This is a one-message-per-file format, where a directory forms
:         the folder and all files in it are messages. The file names are
:         the message numbers.
:         Used by the Rand MH system and derivatives.

   MH format
          This is a one-message-per-file format, where a directory
          forms the folder and the files in it are messages (the
          only exceptions are control and cache files used by
          certain MUAs). The file names are numbers (not necessarily
          in sequence), or numbers preceded by commas.  The files
          with names starting with commas correspond to deleted
          messages. Used by the Rand MH system and derivatives, and by
          Mutt.

:  MBX format
:         Not directly understood by Procmail, but there is a patch. Used
:         by Qmail (?)
:         More details welcome.

    AFAIK, Qmail doesn't handle MBX mailboxes.

:  Maildir format
:         Not directly understood by Procmail, but you can call up an
:         external program for each delivery. Used by some IMAP systems.
:         A Maildir folder is a directory, with three subdirectories
:         named "tmp", "new", and "cur". Messages are written into "tmp",
:         then moved to "new" to commit the delivery. As messages are
:         read, they're moved from "new" to "cur", and renamed to append
:         flags for the message status. In Maildir folders the files have
:         long, complex names intended to ensure that all filenames are
:         unique. Maildir is the only mail folder format that requires no
:         locking.

   Maildir format
          Not directly understood by Procmail, but you can call up an
          external program for each delivery. A patch for Procmail is
          equally available at the Qmail home page.  Used by Qmail
          and Mutt.  A Maildir folder is a directory, with three
          subdirectories named "tmp", "new", and "cur". Messages
          are written into "tmp", then moved to "new" to commit the
          delivery. As messages are read, they are moved from "new" to
          "cur", and renamed to append flags for the message status.
          These files are "rigid", their contents is not changed when
          message statuses change.  In Maildir folders the files have
          long, complex names intended to ensure that all filenames are
          unique, even across different machines. Maildir is the only
          mail folder format that doesn't require locking.

    On a related topic, please note that Mutt can natively read and
write both mbox, MMDF, MH and Maildir mailboxes.

Open questions in Appendix B (mail folder formats) include:
[...] 
  * What uses maildir format (program names)?
[...] 

    Qmail and the related utilities, ezmlm (a MLM written by the group
around the author of Qmail), Mutt, possibly also Exmh.  The current
maintainers of C-client have announced that they _don't_ intend to
support Maildir (the most notable MUA that uses C-client is Pine).

  * Anybody have details on the various orphan mbox variant formats? 
    I remember Jamie Zawinsky posted something to comp.mail.misc once 
    but I also seem to recall his post referred back to some earlier
    posting of his or something ...
[...]

    The format of the "From_" lines used by all reasonably recent
versions of sendmail (which is the only one that really matters these
days IMO) is:

        From <address> <date>

where <address> is an RFC822 address and <date> is a date in ctime(3)
format, that is, something like

        Mon Sep 21 00:17:46 1998

    Regards,

    Liviu

-- 
Dr. Liviu Daia                   e-mail:   daia(_at_)stoilow(_dot_)imar(_dot_)ro
Institute of Mathematics         web page: http://www.imar.ro/~daia
of the Romanian Academy          PGP key:  finger 
daia(_at_)stoilow(_dot_)imar(_dot_)ro

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