Zitat von Paul Koning <paulkoning at comcast.net>:
> On Apr 27, 2016, at 9:07 AM, emu at 
e-bbes.com wrote: 
 
   If
"accurate" means to run VMS or Unix, it shouldn't be to difficult. 
 You might be surprised. 
 
Probably not. I have both working here as Software emulations ;-)
  Getting a PDP-11 FPGA to be accurate enough  to run
standard
 operating systems is hard enough (as I found out  helping Sytze's
 "pdp2011" project).  And that's a much simpler CPU  than VAX.  In
 particular, the privileged architecture tends to be  critical for
 getting an OS to boot, and that part tends to be poorly  documented
 (as well as variable from one CPU model to the next). 
Funny as it Sound, the VAX was easier, but all the Floating Point
formats took a while to implement ...
  I don't know.  Fun is certainly a good reason for
many of us. 
Yup, that's how it started ;-)
  I don't know if there are any unexpired patents;
if not, then
 implementing a machine from the published documentation seems fine,
 though running the software might require answering some licensing
 questions. 
That's the real pain in the neck, to Transfer licenses from one
machine to the next ...
Cheers