Subject: Re: POP client???

From: Joe Brennan <[email-masked]>
Date: Wed, 15 Feb 95 13:35:44 EST

I think people are going to Pine for the user interface.  Whether the
backend should be IMAP or POP is a separate issue.

We're getting pine to run POP because we want to distribute the CPU
load over 8 login hosts in our unix cluster instead of running
hundreds of IMAP processes on our one mailhub.  Also involved in this
choice is that we want users to keep mail in mbox and not spool, for
disk quota reasons; so a connection to mailhub and the spool is needed
solely to move new mail in, which is already a POP model.

Now the University of Washington want IMAP, and we should recognize
they have no great interest in designing and testing a POP
implementation they won't use.  We shouldn't expect them to write it
for us.  If that's what Ed is trying to say, OK.  But don't act like
IMAP answers all needs.

What does the mail system at Washington look like, anyway?  Just out
of curiosity.  What is the imap host and how many users is it
handling?  Ours is a Sparc 20 and we have 20,000 accounts with over
40,000 messages delivered daily... can't do much imap on that guy.

Joseph Brennan     Academic Information Systems
                   Columbia University in the City of New York
                   [email-masked]

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From: "Steven D. Majewski" <[email-masked]>
Date: Wed, 15 Feb 1995 14:17:48 -0500 (EST)

> backend should be IMAP or POP is a separate issue.

Agreed.
 
> solely to move new mail in, which is already a POP model.

But I don't see any reason why you can't configure pine and IMAP to
meet these requirements. Why not distribute the IMAP servers ? 
[ There are a lot of possible mbox/spool configuration, but I'm not
sure what exactly you want. It's hard to propose an alternative 
without knowing the details, but I don't understand why you need 
to funnel everything thru a single IMAP server. ] 

On paper, and from my own limited experience, I would have to judge
IMAP as far superior to POP. But I haven't had experience with it
in a large scale, and one option UVA is considering for their 
university wide mail system would be a IMAP based system, so if there
is a specific reason that you think it won't scale up, I would like
to know. 

---|  Steven D. Majewski   (804-982-0831)  <[email-masked]>  |---
---|  Computer Systems Engineer          University of Virginia  |---
---|  Department of Molecular Physiology and Biological Physics  |---
---|  Box 449 Health Science Center    Charlottesville,VA 22908  |---

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From: Ed Greshko <[email-masked]>
Date: Thu, 16 Feb 1995 10:51:05 -0800 (GMT)

> backend should be IMAP or POP is a separate issue.

	Mostly true.  Some are making their choice "pine" or "ECS Mail"
because they support IMAP and perform better than POP in a mobile
environment.

> solely to move new mail in, which is already a POP model.

	I'm a bit confused here.  IMAP is a superset of POP.  How you
distribute email over various machines is unrelated to what protocol to
use to access individuals email.  Also, (at least on the systems I'm
familiar), them method to invoke "popd" is the same as "imapd".  That is
via inetd.  In both cases a copy of the "daemon" is invoked for each user.

> for us.  If that's what Ed is trying to say, OK.  But don't act like

	Neither POP nor IMAP will be the answer for eveyone's needs.
All I'm saying is pine is designed to work well with IMAP in the same way
the a client such as Eudora is designed to work well with POP.  I believe
would be doing a dis-service to jam either one into the others world.

> 40,000 messages delivered daily... can't do much imap on that guy.

	I believe they have a rather large user community running IMAP
on a not so powerful machine.  (This is from memory of a discussion quite
some time ago on a POP v.s. IMAP discussion.)  

					Ed

Edward M. Greshko                       Technical Manager, Electronic Commerce
                                        Control Data Asia/Pacific Region
Voice: +886-2-715-2222 x287             6/F, 131 Nanking East Road, Section 3
FAX  : +886-2-712-9197                  Taipei, Taiwan R.O.C

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From: Mark Crispin <[email-masked]>
Date: Wed, 15 Feb 1995 22:31:17 -0800

> solely to move new mail in, which is already a POP model.

It seems to me that you're making a number of assumptions about the 
IMAP vs. POP models which are not necessarily true.

Where are the physical bits located?  On an NFS server?  Have you
considered the costs of having all that NFS traffic (remember, the
*entire* mail file needs to be sent over the net when you use NFS).  Have
you considered the locking implications? 

If you don't use NFS, then presumably you lock your users onto a single 
CPU server.  All you've done in that case is move the line between server 
and client.  You haven't saved yourself anything.

IMAP does not add overhead; there is nothing that IMAP does that doesn't
have to be done by a mail program in routine operation.  NFS, on the other
hand, *does* add overhead; the bits aren't where they are needed and the
transfer has much less finesse than IMAP.  POP, too, adds overhead (a
full-message transfer) although by itself this is much less costly than
NFS access. 

The bottom line is that yes, a thoughtlessly-configured IMAP
infrastructure is theoretically worse than POP.  It is also true that POP
allows you fewer opportunities to do something stupid.  But I don't
advocate thoughtless configurations. 

In terms of the CPU costs of IMAP, the computer center's IMAP servers
(RS/6000s) ran out of disk I/O bandwidth (due to sendmail queue
processing, not IMAP!), without the slightest hint of running out of CPU
or memory (they use tenex, not mbox format; this saves lots of memory and
disk access).

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From: David L Miller <[email-masked]>
Date: Wed, 15 Feb 1995 16:06:35 -0800

On 14 Feb 1995 chris@PROBLEM_WITH_INEWS_GATEWAY_FILE wrote:

> Date: 14 FEB 1995 13:48:11 GMT
> From: chris@PROBLEM_WITH_INEWS_GATEWAY_FILE
> Newgroups: comp.mail.pine
> Subject: Re: POP client???
> 
> Kevin Flanagan (kevin@PROBLEM_WITH_INEWS_DOMAIN_FILE) wrote:
> :  I hear that PINE can be configured to be a POP client, does anyone here have 
> : a pointer to the document that I need to set this up?
> 
> I've done it by inserting/changing one line in my .pinerc file:
> incoming-folders=POPMail {mailbox.cc.binghamton.edu/pop3}
> 

	incoming-folders=POPMail {mailbox.cc.binghamton.edu/pop3}INBOX

would be better...

> however, i've had some serious problems when using pine as a popmail client
> over a short time period (one week).  I've one user who always get's the
> following message right after connecting to the popserver (this print's after
> it lists some of the headers):
> Bug in Pine detected: "Received abort signal".
> 

This may be a bug and we would like to fix it, but we need more details to
be able to reproduce it... 

On 15 Feb 1995, Joe Brennan wrote:

> Date: 15 FEB 1995 10:44:17 -0800
> From: Joe Brennan <[email-masked]>
> Newgroups: comp.mail.pine
> Subject: Re: POP client???
> 

I have not seen a situation where CPU was the critical resource on an IMAP
server.  Our central systems use a homegrown distributed quota system, so
that is not an issue for us... 

> for us.  If that's what Ed is trying to say, OK.  But don't act like

IMAP is perfectly capable of operating in the POP model, but Pine does not
currently support that model, except by a side-effect of the mbox driver. 
That is why we have been very hesitant to talk about the POP drivers in
Pine 3.91. 

> 40,000 messages delivered daily... can't do much imap on that guy.

One of our central clusters includes about 24 login servers and 12 IMAP
servers (AIX boxes, I'm not sure what model) to support around 45,000
accounts.  There are also a significant number of PC-Pine users connecting
to those IMAP servers, but I don't have any numbers.  The IMAP servers are
configured for Tenex folders and have no problem with CPU load. 

--DLM

|\ |  |\/|  David L. Miller    [email-masked]  (206) 685-6240
|/ |_ |  |  Software Engineer, Pine Development Team   (206) 685-4045 (FAX)
University of Washington, Networks & Distributed Computing, JE-20
4545 15th Ave NE, Seattle WA 98105, USA

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From: [email-masked] (Leslie Mikesell)
Date: 18 Feb 1995 17:19:37 -0600

In article <[email-masked]>,

>configured for Tenex folders and have no problem with CPU load. 

Out of 45,000 accounts you *must* have a few people who travel to places
where it is at least a long distance call to get an internet connection.
How do you handle the people who want to quickly download their mailbox
to their notebook machine and work offline?

Les Mikesell
  [email-masked]

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From: Terry Gray <[email-masked]>
Date: Sat, 18 Feb 1995 21:23:24 -0800 (PST)

> to their notebook machine and work offline?

True, and not very well (yet).  We even have folks who would like full
disconnected operation, not just offline mode... Both of these are on the
to-do list. 

-teg

---

From: Mark Crispin <[email-masked]>
Date: Sun, 19 Feb 1995 14:40:22 -0800

> to their notebook machine and work offline?

I've done it.  It's a little more manual than people of clients such as 
Eudora are used to, but it is doable now.

In Pine, that is simply an aggregate save to a local file on the notebook
machine.  Not very automatic, so we don't advertise Pine as an "off-line
client"; you actually have to type 4 characters plus a file name. 

Similar, offline composing of messages is also possible, as long as you 
postpone messages each time (PC-Pine).  In Unix pine on a laptop, you let 
the sendmail on the laptop worry about it.

Generally, I prefer to spring for the long distance phone call unless I'm 
in a airplane (or I can use our INWATS).