.SH
Introduction and History
.PP
The Multi-channel Memo Distribution Facility,
commonly called MMDF,
is a suite of software that has seen a great deal of work since it was
originally released in 1980.
The original code was designed and implemented by Dave Crocker
working under Professor David Farber at the University
of Delaware (UDEL).
The MMDF system was then chosen to form the initial backbone
software for the CSNET project and has been in use for several years
by elements of the U.S. Army.
The software has seen a great deal of change in the process.
The original code is commonly referred to as MMDFI or MMDF Version 1.
A number of minor additions and changes were made while fielding MMDFI
as the result of collaboration between UDEL and BRL and some other
sites.
After the original code was fielded in CSNET, Dave Crocker began the
development of a upgraded version of the MMDF system which was
designed to work in the new Internet
domain naming system
and was to incorporate numerous design changes suggested by
experience with MMDFI.
Dave Crocker
left the CSNET project before completing this work, approximately
two weeks before the TCP/IP switchover of the ARPANET, 1 January 1983.
At this time, BRL was a solid MMDF site.  
We were reluctant to try to retrofit
the existing version of MMDFI
to handle the new mail protocols that also took effect on
1 January, so Doug Kingston of
BRL undertook the task of finishing the work
needed to make MMDFII operational.
A production version of MMDFII was installed at BRL during
the third week of January 1983, and served
as BRL's mail system on three hosts,
but there was no stable version of the MMDFII code until June 1983.
The first few months of MMDFII
were quite rough and it needed a great deal of ``tender loving care''.
.PP
For reasons that will be clear in a moment, this stable version of June 1983
is now referred to as the MMDFII-pre-England version.
Around June, a copy of this stable version was delivered to Steve Kille
of University College London (UCL) and to Brendan Reilly
of UDEL, who
had taken over Dave Crocker's work on MMDF at UDEL.
Steve Kille made a number of major changes to the handling of domains,
address parsing, and handling of the alias files.
Steve also added support for NIFTP, a European file transfer protocol
used for sending mail in a batch environment.
At the same time that
Steve was making his enhancements, Doug Kingston continued
to develop BRL's copy of MMDFII to make it an even more solid
mail system.  BRL's changes were not as major as Steve's
but covered a great deal of code and fixed several major outstanding bugs.
This dual development led to two variants of MMDFII that each
needed the other's improvements.
In late September of 1983
Brendan Reilly and Doug Kingston spent a week in England with Steve
to merge the variants and to discuss future changes and directions
for MMDF.  The result of this meeting was a merged version of
MMDFII which I will call MMDFII-post-England.
Just prior to this trip, the CSNET Information Center (CIC)
received a copy of the pre-England MMDF.
Their later changes were based on this pre-England version
which made merging of their changes into the
post-England version somewhat difficult.
.PP
After the England meeting, Brendan Reilly of UDEL took the role
of coordinator of the subsequent changes to MMDF.  Copies of the
MMDF-post-England were made simultaneously available to BRL, UCL, and UDEL.
Since then many minor changes have been made by all
four sites;
in essentially all cases these changes have been bug fixes or changes
to make MMDF a more stable and robust system.
.PP
Since then, Doug Kingston at BRL has made changes
to the local delivery mechanism, rewriting much of the original
code, and the central delivery program has been upgraded to
take advantage of large-address-space machines, when possible, to
keep retry histories for messages on a host-by-host basis.
Bernie Cosell at the CIC has undertaken to speed up MMDF
execution by providing a facility for compiling in some of the information
normally included in the ASCII text-based version.  Steve Kille
an alternative to the ASCII text based version.  Steve Kille
has continued to refine the address handling and the British
``backwards'' domain code.
.FN
The British do domains backwards.  For example, if in the
US (Internet) we write ``user@VAX1.EE.UDEL.ARPA'' known
as ``little endian'' order, the British
(SERC Net) 
write ``user@ARPA.UDEL.EE.VAX1'' or ``big endian'' order.
Put another way, ``big endians'' put the largest, most general,
or most significant element of the domain first.  ``Little endians''
use the other order, with the most significant part last.
[See 
.I
Gulliver's Travels
.R
by Joanthan Swift.  The "big endian" vs. "little endian" controversy
was a 
.I
causus belli
.R
in Lilliput.]
.FE
Brendan Reilly has made changes to the package to allow it to
run on the Altos system and has fixed numerous bugs in
the PhoneNet code.