🚀 go-pugleaf

If you want the C source code for an xmodem program that runs on unix, 
and can probably be adapted to the IBM-PC, it's available in
the public FTP directory on host UCSD.EDU, as well as many other places.

If you're totally twisted, there's one in the same place that runs on
VMS, and is written in Fortran (fornitran?).

There's nothing proprietary about the xmodem protocol and many programs do
it.  In fact, I once assigned xmodem as a programming exercise in a course
lo these many years ago.

Certainly, other variations on the xmodem (ymodem, zmodem, abcdefmodem) 
theme are improvements, but the original still works pretty well, and 
it's extremely easy to implement.

I'll wager you could even write it in BourneShell, if you were on really 
good pharmaceuticals some boring weekend.  After all, someone already
wrote a BASIC interpreter in shellscript, so why not xmodem?
	- Brian