XMODEM file transfer question on 2.11 BSD

[Mark Lawler]

I found the zmodem sources in /usr/src/local/zmodem on my PiDP and made them.  This results in the program files rx, rb, rz, sx, sb, sz being deposited in /usr/local and a new manual entry created for these file transfer commands (i.e. man rx).  

However, if I run a command like rx file.txt (with or without the -a or -b switches) and then fire up either XMODEM or XMODEM1K from Windows ExtraPuTTY, after a few packets claim they've successfully transferred to the PiDP-11/70 by ExtraPuTTY's side of the house, the PiDP side eventually throws the error "syntax error:  'newline' unexpected."  

Inspection of /tmp/rzlog shows checksum errors.

     rz: ready to receive compasc.com

     Retry 0: Checksum

     Retry 1: Checksum

     Retry 2: Checksum

     Retry 3: Checksum

     Retry 4: Checksum

I have things set up for 9600 baud, 7E1. I've tried playing with various settings for parity, flow of control, etc. but...  It looks like the first packet makes it to disk correctly, but...  Also looks like ExtraPutty thinks multiple packets are going over okay as it continues to chug along with the next packets until the PiDP-11 side gives out.

Anybody been able to get this to work?

Best,

-Mark

[Heinz-Bernd Eggenstein]

I haven't played too much with it, but so far cannot reproduce any problems, seems to work for me. My setup is a bit different tho:

PiDP11 on a RaspI4 <=> USB-RS232 adapter <=> null modem cable <=> Maxim 232 based RS232 to GPIO adapter <==> Raspberry PI <=>  minicom program

All setup for 9600 7E1 . After calling rx  -a  somefile.txt on the PDP11-side, I can initiate an XMODEM transfer in minicom and the text file is transferred just fine.

Sorry that won't help you much, except demonstrating that there is nothing fundamentally broken on the PiDP11/simh  side  I guess.

Maybe some strange CR/LF handling on the Windows side???

Cheers

HBE

[Tony Nicholson]

On Saturday, July 3, 2021 at 3:19:31 AM UTC+10 Mark wrote:

[snip]

 

I have things set up for 9600 baud, 7E1. I've tried playing with various settings for parity, flow of control, etc. but...  It looks like the first packet makes it to disk correctly, but...  Also looks like ExtraPutty thinks multiple packets are going over okay as it continues to chug along with the next packets until the PiDP-11 side gives out.

Anybody been able to get this to work?

Best,

-Mark

The Ward Christensen Protocol (XMODEM) needs an 8-bit clean serial interface due to its use of 8-bit “block numbers” and checksums in the headers around each 128 bytes of the 8-bit data in each “packet”.

Try using 8N1.

See. https://en.wikipedia.org/wiki/XMODEM

Other protocols like Kermit use encoding of 8-bit and non printing characters to work on 7-bit US ASCII (and EBCDIC) character lines.

Tony