🚀 go-pugleaf

In article <DJM.92Mar9194708@frob.eng.umd.edu> djm@eng.umd.edu (David J. MacKenzie) writes:

>   Processing MH folders a lot of overhead from opening lots of files
>   and wastes a lot of disk space because of minimum fragment sizes.
>   Other than those problems, they're ok.

I agree with the statement about slowness due to finding and opening
many files.  The difference in disk usage between storing messages
individually and storing them in one big file is usually not that
significant, except for users who get a lot of really short (1 or 2
line) messages.  I get some messages like that, but most of the ones I
save wind up being 1 or 2K anyway, so I find that I save only about 15%
in disk space by storing a large number of mail messages in one file
rather than separately.  Users who have 1000 messages that look like:

	From: joe@foo.bar.com
	Date: Tue, 10 Mar 92 00:00:00 GMT
	Subject: Lunch

	Let's have lunch tomorrow.

	-joe

tend to save up to 30% by storing in one big file.  Of course, they'd
save a lot more by throwing away the mail headers, in this case.

I dislike MH in general for several reasons I won't get into now, but I
have to admit that the one-message-per-file philosophy has several
advantages:

	1. Easier manipulation of individual messages.
	2. Much lower probability of catastophic mail loss in
	   event of system crash or program bug which occurs
	   while reading mail.  Usually only one message at most
	   will be lost, rather than entire folder.
	   (This point can't be brushed aside easily; the 
	   manipulation of files larger than a megabyte triggers
  	   obscure bugs in several programs and filesystems.)
	3. Programs reading such files can be written to use less
	   memory than programs which have to hold entire folder
	   in memory at once.  This means reduced swapping and less
	   likelihood of running out of memory on low-end or 
	   heavily-loaded systems.

I would like to see VM be able to manipulate messages in some
one-message-per-file format, especially if it is optional; i.e., I still
would like to be able to read UNIX mbox-style mail folders, easily
burst the messages into individual files, and get them back into one
file, preferably all within VM.

-Calvin
--
Calvin Clark <ckclark@mit.edu>