Remote job submission from PDP-11

Peter Coghlan cctalk at
Wed Oct 7 14:23:18 CDT 2020

> Hi folks,
> I am looking for the following software products for a PDP-11, ideally to
> be run on RSX-11M.
> 2780/3780 Protocol Emulator
> My aim is to be able to submit a remote job from a simulated PDP-11 on simh
> to a simulated IBM/370 on Hercules. The products that I mentioned seem the
> obvious way to do this, but anything that works would be helpful.

I suspect the products you mention above are designed to interface to a
real synchronous serial line?  In my experience with Hercules, simulating
a generalised synchronous serial line effectively in software is pretty
fraught.  I don't know if simh attempts to do this or if it allows the
simulated system access to real synchronous serial hardware in the host
system.  If the latter, this doesn't get you any closer to a connection to
Hercules because Hercules does not have code to drive a real synchronous
serial line.

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.

Or, it might be possible to use an intermediate gateway such as a MicroVAX
with a synchronous serial interface.

The protocol used for 2703 over TCP/IP emulation in Hercules is not really
up to doing much more than trivial RJE transfers.  It can't really manage
NJE either. (NJE is mostly just RJE with another layer added on.)

Back in the 1980s, a requirement arose to be able to transport NJE across
the internet for the BITNET network.  A protocol was devised to enable this
to be done effectively:

I have implemented this protocol in Hercules here:

Unfortunately, this protocol is specific to NJE, it does not work for RJE.
In order to get RJE in and out of Hercules with any degree of reliability
and efficiency, it would be necessary to come up with an equally suitable
protocol or tweak the NJE protocol appropriately.

If you can come up with a way of getting NJE over TCP/IP out of your
simulated PDP-11 on simh, you can trivially connect that to my code in
Hercules in order to end up with NJE connections to either VM/370 RSCS
or MVS (both with suitable tweaks).  Not so useful if what you really
want is RJE though.

Peter Coghlan.

> Cheers
> Peter Allan

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