Digital VAX, Alpha (Was RE: Mac "Workgroup Server" ...

emu at emu at
Thu Apr 28 03:02:43 CDT 2016

Zitat von Paul Koning <paulkoning at>:
>> On Apr 27, 2016, at 9:07 AM, emu at 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 ...


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