From comp.mail.mime_FAQ,_part_2_of_3 :
Name: mpack
Product: MUA/utility
Platform: Unix, MS-DOS, OS/2, Macintosh, Amiga, Archimedes
Contact: mpack-bugs@andrew.cmu.edu
Where: ftp://ftp.andrew.cmu.edu/pub/mpack/mpack-1.5-src.tar.Z
Sources for all versions
Where: ftp://ftp.andrew.cmu.edu/pub/mpack/mpack15d.zip
MS-DOS binaries
Where: ftp://ftp.andrew.cmu.edu/pub/mpack/mpack15o.zip
OS/2 binaries
Where: ftp://ftp.andrew.cmu.edu/pub/mpack/mpack-1.5-mac.hqx
Macintosh binary
Where: ftp://ftp.andrew.cmu.edu/pub/mpack/mpack-1.5-amiga.lha
Amiga binaries
Where: ftp://ftp.andrew.cmu.edu/pub/mpack/mpack-1.5-arc.arc
Archimedes binaries
Where: ftp://ftp.andrew.cmu.edu/pub/mpack/mpack-1.5-linux.tar.gz
Linux binaries
Author: John Gardiner Myers, Chris Newman (Mac), Mike Meyer (Amiga),
Peter Simons (Amiga), Jochen Friedrich (OS/2),
Olly Betts (Archimedes)
Comments:
[ John Gardiner Myers <jgm+@cmu.edu> 16-Feb-1995 ]
Mpack is a minimal implementation of MIME, designed for encoding and
decoding binary files in MIME messages. In short, it is the MIME
equivalent of uuencode and uudecode. For backwards compatibility,
it can also decode messages in split-uuencoded format. The Macintosh
port can also handle AppleSingle, AppleDouble, and BinHex.
Starting with version 1.5, all official mpack distributions are
PGP signed by "John Gardiner Myers <jgm+@cmu.edu>". The PGP
signatures are detached from the distributions themselves, in
files with the ".asc" filename extension.
[ Arjan van der Meer <arjanvdm@htsa.hva.nl> 30-Jan-1995 ]
There is now a version of mpack/munpack for the Atari ST and
compatibles. It is just a compiled version of the UNIX 1.2 version,
but what I've tried worked okay. It is made by alex@hal.rhein-main.de.
MPACK/MUNPACK Atari ST binary -
ftp://ftp.uni-kl.de/pub/atari/misc/mpack_12.lzh