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
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