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Re: New Vax - future directions :-)

On 2021-07-07 15:47, Paul Koning wrote:

On Jul 7, 2021, at 9:34 AM, Johnny Billquist <bqt%update.uu.se@localhost> wrote:

On 2021-07-07 15:03, Paul Koning wrote:
On Jul 7, 2021, at 8:02 AM, Johnny Billquist <bqt%update.uu.se@localhost> wrote:

On 2021-07-07 13:37, Anders Magnusson wrote:
Den 2021-07-07 kl. 11:37, skrev Hans Rosenfeld:
And, can we perhaps get a PDP11 compatibility mode, too? Like the one
early VAX-11 models had? Please? :)

Thanks for breathing some life back into the VAX, and into port-vax.
This is so amazing on so many levels. :)
Hm, I haven't thought of that before, but it might be quite trivial to do that.
Almost no extra hardware, just a separate match for the microassembler.

I'd be a little curious on why anyone would want it, though. (Even me, being a PDP-11 fanatic, isn't that interested in this compatibility mode...)
It allows running early VMS releases.

Ah. True. But would you even try to do that on some new FPGA implementation of a VAX?
Then you'd have to pretty faithfully implement all peripherals and other details of the VAX-11 machines. All the internal registers specific to that machine, and so on...
If I wanted to run old VMS, seems like simh would be a simpler way.

It would, but doesn't SIMH need work to be able to install VMS V1?  I seem to remember that it requires a more complete emulation of the console than is currently available.

Not sure. I believe I've read about people getting VMS V1 up and running, but I don't know if it required some fiddling around.

But I still sortof fail understanding why something like the Ragge FPGA VAX would be interesting to have PDP-11 emulation on. Like I said, I seriously doubt it would be capable of running early VMS for multiple other reasons. And the PDP-11 mode in the VAX have limitations that makes it much less attractive than any normal PDP-11.


Johnny Billquist                  || "I'm on a bus
                                  ||  on a psychedelic trip
email: bqt%softjar.se@localhost             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol

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