From lloyd@cs.toronto.edu Mon May 29 10:33:24 2006
Date: Mon, 29 May 2006 10:32:48 -0400 (EDT)
From: Lloyd Smith <lloyd@cs.toronto.edu>
To: office-staff@cs.toronto.edu
Cc: Lloyd Smith <lloyd@cs.toronto.edu>
Subject: Re: Your CSLab mailbox



Occasionally some of you will get mail from Bev or one of the
other CSLab staff that looks something like this: 

On Fri, 26 May 2006, it was written:

> I'm writing to you because your CSLab mailbox (in /var/mail) is over
> 100Mb in size.  Space is getting tight in /var/mail again, and the
> mailboxes used by the recipients of this letter are taking up an
> entirely disproportionate fraction of the space shared by over 1000
> users.

Just to be clear on what Bev means, this is your *inbox*, not any 
mail folders you have created.

Briefly email is delivered to shared filespace (in /var/mail/ ). 
This is analogous to Canada Post delivering your postal mail to
a superbox. 

<ASIDE>
In case you aren't familiar with superboxes, if the street you 
live on is less than 20 odd years old, you do not get home 
delivery. Instead your mail is left in a (locked) cubby hole in 
a box on the corner. See 
http://www.flickr.com/photos/tdl/41297952/in/set-1042755/
for an example. 
</ASIDE>

Periodically you go and check your mail. Though Canada Post assumes 
you are going to empty your cubby, nothing prevents you from just 
putting it back in and locking it up again.

Unlike a superbox, the size boundaries of your inbox are "stretchy",
but the total size is limited by how much disk space is available 
for everyone to share. As your usage expands you squeeze the space 
left for everyone else. 

You can check your email and either delete it, leave it in the inbox, 
or you can move it to a folder in your home directory (i.e. H:\mail\ 
from Windows or $HOME/mail from unix). Mail that you save to your
home directory does *not* count in your mail usage. 

This is different in two ways from most other email providers you 
might be familiar with (e.g. your ISP or UTorMail), where only 
your total usage is counted (ie. inbox plus saved mail), and secondly
delivery stops if you hit the wall. 

A one page plain text email message would be about 10 kB or 
0.01 MB meaning 100 MB is enough space to store 10,000 messages. 
If you sort your inbox by size you will almost certainly find you
have a small number of messages that have large attachments. 

In the paper world this is like when your great aunt mails you
a big bulky sweater that she knit for you. If instead of leaving
it in your superbox cubby you bring it home with you and store
it in your dresser drawer there will be room for thousands of 
regular size letters. 

If you are like me and let email accumulate until you really do 
have 8000+ messages stashed away there is no choice but to do 
some filing. <sigh> I create a directory named after the year and 
folders for each month. I make the names of the folders start with 
YYMM so they sort by date (otherwise Apr would be first and Sept last)

e.g.
 2006/-/0601(Jan)
      +/0602(Feb)
      +/0603(Mar)
      ... 

Finally you can create email processing rules in two special 
files in your home directory ".forward" or ".procmailrc". This
is like leaving a note taped inside your cubby with instructions
for the Canada Post worker explaining what to do with certain
mail. It is mostly useful if you get lots of spam (where "lots"
means over 100 messages a day), but it can be used for when 
you are on vacation to have an auto-reply fire off to whoever 
just sent you mail.  

This 

HTH,
lloyd