mrc@Tomobiki-Cho.CAC.Washington.EDU (Mark Crispin) (03/23/90)
Recently there have been a lot of messages on TCP-IP asking about
POP-based software. There is an alternative to POP, IMAP, described
in RFC-1064. The IMAP protocol is technically superior to POP; it
provides significantly more advanced server functionality (including
server-based RFC-822 parsing and a server-based search engine) which
allows for simpler, yet more powerful, clients.
We've been chary about advertising, since we're actively working on
various IMAP-based tools and don't want people to get the wrong idea
about our software based on incomplete development versions. However,
that doesn't mean that IMAP is vapor; it's been in use at Stanford
University, the University of Washington, NTT, and other organizations
for years.
A beta IMAP distribution is available for anonymous FTP as
pub/imap.tar.Z from Internet host ftphost.CAC.Washington.EDU, IP
address [128.95.112.1]. On Unix, the commands "uncompress imap.tar.Z"
followed by "tar xf imap.tar" will give you an IMAP directory.
This distribution includes:
(1) IMAP client for Xerox Lisp (no further development planned)
(2) IMAP server for DEC-20/TOPS-20 (no further development planned)
(3) IMAP server for BSD Unix (contact yeager@SUMEX-AIM.STANFORD.EDU
for updates; this software is under
active development)
(4) Portable IMAP client library in C, with OS-dependent interfaces
for BSD Unix, TOPS-20, Macintosh, and MS-DOS.
(4a) portable "test" IMAP client
(4b) BSD Unix IMAP client with MM-like interface
(4c) NeXT GUI client in advanced and stripped-down form (contact
me for updates; this software is being
changed daily)
Sources to everything except for (4c) are included. In addition,
Stanford University has developed a Macintosh client; contact
yeager@SUMEX-AIM.STANFORD.EDU for information on how to obtain a beta
copy. I have been contacted by various individuals who are developing
MS-DOS clients; I don't know if any have been released yet.
The main thrust of my recent efforts has been in the NeXT client. I
should caution that the NeXT GUI client is still in beta test and that
one functionality (the address book) doesn't work at all. However, it
has been operable enough for me to use as my primary mail UA for a
year now.lane@sumex-aim.stanford.edu (Christopher Lane) (03/24/90)
Just to add a voice of support to Mark's note regarding IMAP: I've been using the NeXT IMAP client exclusively (except when dialing in from home) for the past year as well. Previous to that, I used the Xerox Lisp IMAP client for over a year (talking to both Unix and TOPS-20 servers). We've many Macintosh IMAP client users as well and the number is growing. Mark didn't mention one other (undistributed) IMAP client implementation, written in CommonLisp for the TI Explorer which is the most experimental and powerful of the IMAP clients and will hopefully yield new ideas for the other clients. Although IMAP isn't the most advanced system (yet!) with respect to things like multimedia, the effort so far has gone into it's design generality and applicability to numerous, heterogeneous workstation environments as well as optimizing/minimizing data transfer. My opinion is biased as I work for SUMEX-AIM which provides the Unix IMAP server (and several clients). I was also directly involved with IMAP in the final sorting out of the (original) Xerox Lisp client and design of the window & menu layout incorporated in subsequent clients. But trust me, it's great! - Christopher -------
lear@turbo.bio.net (Eliot) (03/24/90)
In IMAP, you've advertised as as a feature great server search facilities, and the fact that the server protects the client from as much state as possible. It would seem to me that such an approach would produce a bottleneck of server resources far faster than POP would. In a large scale arena such as SUMEX, would it not be better to design a protocol where you assume that the free cycles will be on MANY client machines, rather than a few servers? I suppose taken to extremes I should stick to FTP, but I would see where both POP and IMAP (and FTP) have their places... -- Eliot Lear [lear@turbo.bio.net]