External bus interface

[Lars Brinkhoff]

Hello,

I'm adding something to the mainline SIMH PDP-11 simulator that may be of interest to this group.  (Do we use stock SIMH or a fork?)

It's an external bus interface.  Through a TCP/IP port, you will be able to peek and poke PDP-11 memory locations and hardware registers.  No need to pause the PDP-11, this works at run time.

For the best experience, I recommend using a PDP-10 running ITS at the other end. :-)  This provides a full PDP-11 cross development environment with cross assembler, simulator, remote programming and debugging.  But any application that speaks the bus protocol will do.

[dwegs...@gmail.com]

This could be interesting: would we be able to use this to stuff data into arbitrary addresses in the IO address space?

If so, it could be a generalized way to interface arbitrary real devices to the PDP-11 software; instead of having to compile the code for the temperature sensors into simh, that interface could be done by an external-to-simh process and the data stuffed into simh via this facility?

[Lars Brinkhoff]

dwegscheid wrote:

This could be interesting: would we be able to use this to stuff data into arbitrary addresses in the IO address space?

The PDP-10 could read and write the Unibus IO space, so yes.

 

If so, it could be a generalized way to interface arbitrary real devices to the PDP-11 software; instead of having to compile the code for the temperature sensors into simh, that interface could be done by an external-to-simh process and the data stuffed into simh via this facility?

I imagine people will want to do this, but currently my addition doesn't support this use case.  My application is a PDP-10 sending read and write requests on the Unibus, to access core memory and I/O devices simulated in SIMH.  Requests from the PDP-11 CPU will remain inside SIMH.

However, I believe it will be possible to generalize the protcol in the future.

[Oscar Vermeulen]

Lars,

On Sat, 28 Jul 2018 at 09:53, Lars Brinkhoff <lars.br...@gmail.com> wrote:

I'm adding something to the mainline SIMH PDP-11 simulator that may be of interest to this group.  (Do we use stock SIMH or a fork?)

A recent fork. But changes in simh are easy integrated (Jörg Hoppe did it not too long ago), so no problem.

 

It's an external bus interface.  Through a TCP/IP port, you will be able to peek and poke PDP-11 memory locations and hardware registers.  No need to pause the PDP-11, this works at run time.

Nice!

 

For the best experience, I recommend using a PDP-10 running ITS at the other end. :-)  This provides a full PDP-11 cross development environment with cross assembler, simulator, remote programming and debugging.  But any application that speaks the bus protocol will do.

Good thing the PiDP-10 will have an Ethernet port as well ;)

Now for some time to finish that prototype...

Kind regards,

Oscar.