Date   : Thu, 13 Oct 1983 08:29:00 cdt
From   : Ronald W. <Heiby@hi-multics>
Subject: UMODEM 3.6 problem?

I have compiled UMODEM 3.6 on a Wicat 150 under Unisoft's port using the
SYS3 define and VAX/11-780 under 4.1bsd using the VER7 define and in
both cases I have the same problem.  To get umodem onto the two systems,
I used ftp to get it to my main host (HI-Multics), used the MODEM2
protocol to get it to my home CP/M system, then raw dumped it up to each
of the other two systems (incompatible media, etc.).  After making sure
there were no line glitches, I compiled the programs as above and used
them to try to transfer the same UMODEM 3.6 source up again, so that I
could compare the two copies.  I wanted to make real sure that there
were no hidden problems in the original source transfer.  What I got was
the first block of data, then UMODEM thought that it had received the
end of file.  MDM712 still thought it was doing a transfer until it did
its ten retries on block two.  I did this several times and the problem
was with the same first block each time.  Other files worked ok.  I
tried deleting an asterisk from the first 128 bytes of the file, then it
transferred fine until much later in the file.  I figure that it must be
a problem with some checksums.  The checksum for that block was 1CH (if
I figure it right).  After fudging things by making minor changes to the
offending blocks, I was able to send UMODEM 3.6 to the Wicat and, except
for my two changes to comments, compared identically to the original.
Anyone have any ideas?  Thanks.  Ron <Heiby @ HI-Multics>.