Subject: Re: IMAP Pine vs. Shell account

From: John Gardiner Myers <[email-masked]>
Date: Thu, 2 Mar 1995 16:14:58 -0500

David L Miller <[email-masked]> writes:
> One of the advantages of using a dedicated IMAP server without shell
> access is that we can safely switch to a more efficient format for mail
> folders (Tenex).  Without Tenex, the IMAP servers would use much more
> memory and do more paging... 

Or you could use the Cyrus IMAP server, which uses an even more
efficient format for mail folders.

See http://andrew2.andrew.cmu.edu/cyrus/cyrus for more information.

[email-masked] writes:
>  And Fourth, assuming students have non-shell access to usenet, how
>  would they store their personal subscriptions
>  (server, diskette, ... )?

If the users access usenet through the IMAP server, their personal
subscriptions are stored on the IMAP server.

-- 
_.John G. Myers		Internet: [email-masked]
			LoseNet:  ...!seismo!ihnp4!wiscvm.wisc.edu!give!up

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From: [email-masked]
Date: Thu, 02 Mar 95 09:27:06 CST

Recently Terry Gray described how email is handled at UW.
 I was especially interested in the description of the following:
 
 .....   The cluster includes 12 IMAP servers, although 4 were just added
 to accommodate expected growth.  We figure each of these IMAP servers can
 handle at least 200 concurrent sessions .........                , but
 users are not permitted to get a login shell on the IMAP servers.
 
 UW-Parkside is considering using PINE email and we are trying to size an
 appropriate RS/6000 (new server or upgrade a model 360).  I have a few
 questions:
 
 First, I see they do not allow shell accounts.  If shell and IMAP were
 both allowed, how do you think this would effect the max concurrent
 sessions (assuming half the users would use shell)?
 Second, are there other reasons for not allowing shell access?
 Third, would there been any negative implications to not allowing
 shell access?
 And Fourth, assuming students have non-shell access to usenet, how
 would they store their personal subscriptions
 (server, diskette, ... )?
 
 We are very interested in IMAP PINE.
 And thank you Terry for your original post.
 
 Patrick E. Hurley
 Sr. Systems Programmer
 University of Wisconsin - Parkside
 [email-masked]

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From: David L Miller <[email-masked]>
Date: Thu, 2 Mar 1995 10:07:07 -0800

On Thu, 2 Mar 1995 [email-masked] wrote:

> Date: Thu, 02 Mar 95 09:27:06 CST
> From: [email-masked]
> Newgroups: comp.mail.pine
> Subject: IMAP Pine vs. Shell account
> 

One weakness of Tenex in a shell environment is that the folders look like
ordinary text files, but are very difficult to edit without corrupting
them.  Other mail programs also do not understand Tenex format.  These
together would undoubtedly cause support problems... 

>  (server, diskette, ... )?

Users of the IMAP servers access them from shell accounts on other servers
or from PCs.  In either case, they use local storage on the other machines
for configuration information, etc. 

--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

---

From: Mark Crispin <[email-masked]>
Date: Thu, 2 Mar 1995 20:22:29 -0800

>  sessions (assuming half the users would use shell)?

It is rumored that one interactive user is about equivalent to 3 IMAP 
users.

>  Second, are there other reasons for not allowing shell access?

We wanted to have a dedicated machine that would be highly reliable for
our IMAP server.  Interactive systems have all sorts of nasty
variabilities (e.g. an OS bug triggered by an undebugged user program
could crash the system) that dedicated systems do not. 

>  Third, would there been any negative implications to not allowing

It all depends upon what you are trying to do.  We prefer to buy a lot of 
smaller cheaper machines than fewer big machines.

>  (server, diskette, ... )?

This too depends upon the configuration.  It is possible to have 
subscriptions on the IMAP server if you use IMAP for news instead of 
NNTP.

This is also going to become a lot more flexible in the near future.