Subject: Re: IMAP is a failure?

From: [email-masked] (John M. Wobus)
Date: 2 Aug 1994 21:03:10 GMT

In article <[email-masked]>, [email-masked] (Jason Haar) writes:
>Michael S. Robinson ([email-masked]) wrote:
>
>: I think the reason you're seeing this is a change in the point of reference.
>: You are correct that every guide to the internet mentions PINE or ELM for
>: mail.  However, there is a huge trend towards having central servers
>: with many clients around thme (gee, a LAN maybe?).  Anyways, POP has one
>: great advantage for a client/server set-up:  It goes out, does what it needs
>: to do, then closes up shop.  This cuts down greatly on any unnecessary network
>: traffic.  It's also less overhead for the client system.  Every little bit helps.  
>
>?? Are you saying that IMAP can't do that?
>
>As far as I remember - IMAP could be used as a complete POP replacement - 
>you could GET all messages onto your local system and then DELETE them 
>off the server - Ta Da!!

But IMAP doesn't do that.  Who uses it as a simple POP replacement?  Is
anyone defining a POP-equivalent subnet?  IMAP Lite?  If you want to replace
your POP with functionally equivalent IMAP, you get to run the more complex
server and leave your server open to the kinds of server-resource-draining
behavior that IMAP was designed for.

IMAP is great.  But if you are aiming to limit your server resources
by offering only POP-style usage, then IMAP server and client software is
not ready for prime time.

John Wobus
Syracuse University

---

From: Mark Crispin <[email-masked]>
Date: Tue, 2 Aug 1994 16:45:40 -0700

John Wobus writes:
> leave your server open to the kinds of server-resource-draining

Could you elaborate on what sort of ``server-resource-draining behavior'' you
are referring to?  Have you made any sort of statistical analysis about
various distributed email strategies and their relative costs?

I can understand the claim that keeping mail on the server consumes disk
space, but it would be much more expensive for me to buy adequate disk space
on every client that I use for mail than it would be to buy adequate disk
space on a single server.

It is interesting to compare IMAP vs NFS when you talk about resource
consumption.

---

From: [email-masked] (Don D. Worth)
Date: Wed, 03 Aug 1994 11:11:48 -0700

> space on a single server.

I can understand the issue about longer session times over dial-up
connections for IMAP, although I would contend that many users might keep
their dial-up session active throughout the time they are using their
email client, especially if they have their POP client (eg. Eudora)
configured to do immediate sends and they are replying to messages, one by
one, and if they are making a local call.

However, I don't really buy the issue of POP somehow relieving disk space
on the server. In either protocol, you must allocate some disk quota to
each user and implement some sort of space retrieval (or mail bouncing)
system so you can deal with accumulations of unread email. I would
contend, based on the pattern of use among students at our university,
that the bulk of the storage is consumed by unread mail, not mail that has
already been read. What I'm told is that students on average check email
less frequently than do staff, which allows a greater accumulation of
unread mail. We've heard horror stories for departmental email systems
where a student logs on, subscribes to eleventy seven LISTSERV lists, and
then doesn't logon again for a month.

If you set the quota so that it is not practical for students to store
their logs of email history on the server, but only to accomodate a
reasonable accumulation of inbox messages, I suspect there won't be a
whole lot of difference between IMAP and POP as far as server disk space
goes.

For me, the real reason to go IMAP is to resolve the problems of sharing a
single machine among many (e.g. public access workstation) and of sharing
a single inbox among many workstations (e.g. a workstation at home and a
workstation at work). Also, the advantages of shared inboxes, selective
downloads of MIME components, etc.

         Don Worth
         Manager, UCLA Microcomputer Support Office

---

From: [email-masked] (Jason Haar)
Date: 3 Aug 1994 13:12:48 GMT

John M. Wobus ([email-masked]) wrote:

: But IMAP doesn't do that.  Who uses it as a simple POP replacement?  Is
: anyone defining a POP-equivalent subnet?  IMAP Lite?  If you want to replace

Who would want to? All I'm saying is that IMAP contains the functionality
of POP - obviously it isn't POP. But a MUA could be written that uses IMAP
in _exactly_ the same way that POP is used. No-one has done that because
IMAP also allows you to do other things too. 

: your POP with functionally equivalent IMAP, you get to run the more complex
: server and leave your server open to the kinds of server-resource-draining
: behavior that IMAP was designed for.

I'm a bit concerned about your "server-resource-draining" comment - it may
scare off potential users ;-) IMAP _can_ use more resources than POP
because it offers more features - but I wouldn't want people to think it's
some kind of memory-hog... 

--

Cheers,

Jason
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