Date   : Thu, 09 May 1985 18:14:00 MDT
From   : CSTROM@SIMTEL20.ARPA
Subject: YAM modem program documentation available

I thought you might like to know the reason for the appearance of
YMODEM.DOC at this point. Due to the new proliferation of 2400 baud
modems, a lot of people are acutely aware of the shortcomings of
Christensen protocol's use of 128 byte blocks. There has been a
protracted discussion of this on Compuserve's CP/M interest group, and
at present we expect that Ward Christensen will be authoring an
article destined for Byte which will summarize his protocol as well as
suggest an expansion. There is a good possibility that the extensions
will be the YMODEM protocol as implemented in YAM, with or without
some as yet unspecified additions. In fact, the father of YAM, Chuck
Forsberg, may be a co-author.

In the meantime, Irv Hoff is planning on making some modifications to
MDM740 to support 1K blocks. Several of us have lobbied hard for him
to follow the YAM format and I think that he has agreed at least in
princpal. One of the strengths of Christensen protocol is its
simplicity, and YAM expands upon it, adding functionality while not
making the implementation unreasonably complex. In any case, my
feeling is that Ward's article will define the protocol extensions and
if Irv or anone else were to go off on another path, it would only
muddy the waters and damage the universal strength of Christensen protocol.

-Charlie