Usage Case - e-mail

[Joseph Osako <scholr@xxxxxxxx>]

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E-mail is one of the most important applications currently used 
today, and it is crucial for any new system to implement it 
effectively. Fortunately, it is one of the easiest applications to 
implement in terms of Xanadu - so easy that it isn't really necessary 
to differentiate it from 'ordinary' documents. Since it is so very 
common, and since it will be necessary to provide a way to send 
Internet-style mail (as defined in RFC 822 and elsewhere), it is wise 
to at least consider a standard method of mail handling ahead of 
time.

I have worked out a simple scheme for handling mail messages under 
Xanadu, one that could be easily applied to handling fora, chat and 
quick-messaging as well. It relies solely on adjusting the 
appropriate document settings, without adding anything to the overal 
structure of Xanadu.

Essentially, the application would have to provide two things, a 
'send' daemon and an 'incoming message' queue. The message queue is 
the simpler but more important of the two, being a page that the 
incoming messages automagically get linked to by the send daemon. 
When a new link is added, the queue would set of some kind of 
indicator for the user that new mail has arrived.

The send function is where most of the work is done. When a user 
sends a message, the send daemon reads the addresses of the 
recipients, creates a 'privash' group from it, requests that their 
workstations mirror the message (for efficiency), and links the 
message to each of their incoming message queues. Alternatively, the 
send function can just send an announcement to the recipient's 
receive daemon, which then handles setting up the list of 'new mail'. 


In either case, replies are treated as ordinary annotations, except 
that a)they automatically send an announcement to the original 
poster's incoming message daemon, and b)they 'forward' both the 
message and annotation to any new recipients. 

IIRC, _Literary Machines_ outlines a system something like this 
(someone is borrowing my copy, so I can't check to be sure what it 
says).

Now, since this 'mail' is otherwise an ordinary Xanadu document, it 
doesn't suffer from the limitations imposed on current mail systems, 
even extended mail systems like MIME. There are no limits on size and 
content (except perhaps by convention), and formatting follows the 
usual rules for Xanadocuments. However, since it will also have to be 
able to send SMTP/MIME type messages to non-Xanadu recipients, the 
program should warn the user if data or formatting will be lost.

This is just the simplest method I personally could think of; there 
may be better ways to handle mail. Alternate constructions are 
welcome. 


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J Osako
Programmer Analyst, Operating Systems Designer, Notational Engineer
http://www.slip.net/~scholr/resume.html