Remote job submission from PDP-11

Mattis Lind mattislind at
Thu Oct 8 07:42:28 CDT 2020

Den ons 7 okt. 2020 kl 22:19 skrev Peter Coghlan via cctalk <
cctalk at>:

> However, I know of at least two projects which implement bisync line to
> TCP/IP gateways to interface to IBM terminals using additional hardware.
> Perhaps it might be possible to adapt one or both to do RJE?  Here is one
> of them:
> I can't quite put a hand on a url for the other one right now but the
> author posts here regularly so hopefully he will chime in.
Actually Matt Burke's project is about SNA/SDLC, not BSC. He is using the
3705 emulation in Hercules, not the 2703 emulation that is in commadpt.c

I have been working a bit with Hercules and BSC. There are a number of
things that are a bit peculiar with the Hercules implementation since it
simply pushes the bytes it receives from the channel program onto the TCP
socket. All the bytes added by the 2703 itself is omitted. This means:

1. No CRC bytes are sent
2. No leading SYN SYN are sent. SYN can be seen in the stream if added by
the channel program as a time fill.
3. No Trailing PAD is sent.

The read turn-around takes place immediately as soon as the bytes are
pushed into the socket. So if the actual sending of the bytes takes longer
time the 2703 emulation will not notice this. Something that can be
problematic with real world serial lines.

There is a tiny bug in Hercules 3.13 that has to be fixed to get it working
Trying to use BSC in Hyperion-SDL 4.xx causes a core dump.

I have successfully used the Hercules BSC implementation with the bug fixed
to attach a real BSC connected 3270 compatible terminal.
Here are some information:


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