Remote job submission from PDP-11

Chris Zach cz at
Wed Oct 7 08:46:25 CDT 2020

I do have a bunch of Unibus 3270/X.25 boards from a third party vendor. 
Big big boards with a bunch of Z80's on them to do all the protocol 
work. Anyone interested in me digging them out and figuring out what 
they were?

On 10/7/2020 9:41 AM, Ethan Dicks via cctalk wrote:
> On Wed, Oct 7, 2020 at 5:07 AM Peter Allan via cctalk
> <cctalk at> wrote:
>> I am looking for the following software products for a PDP-11, ideally to
>> be run on RSX-11M.
>> 2780/3780 Protocol Emulator
> I used to do this with specialty hardware...
> ... and there were "non-intelligent" mostly-software HASP and 3780
> emulators, but I say mostly-software because you still needed a serial
> interface that could do Bisync (BSC) - like the DP(V)11 or DU(V)11.
> ISTR these chewed up a bunch of CPU, even on a VAX, and that's why we
> had a market for a $2,500 card and $20,000 license.
> While I do have all the code (and a fair amount of the hardware) from
> Software Results, writing a COMBOARD emulator would be rather complex
> - the core is a 68000 (easy enough to start from) with a COM5025 or
> Z8530 for a USART (probably not a ready-to-drop-in chunk of code) plus
> a DMA engine to the host bus implemented in two ways (different
> COMBOARD models).  That last bit would require deep understanding of
> the original hardware.
> There were also intelligent sync serial engines for this from other
> vendors, including DEC (KMC11, and probably a later one but the device
> name escapes me).
>> 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 think the idea is fantastic.  At the very least, after you identify
> a suitable software package for your target, there would need to be
> emulation written for whatever sync serial devices that the package
> can talk to, for the PDP-11 side.  I have no idea what sort of sync
> serial emulation is provided by Hercules, but if you can configure a
> TCP socket that pretends to be a BSC port, then that's what you'd
> need.
> This is eminently do-able, but would likely require a fair bit of
> plumbing to get operational.
> -ethan

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