Ultrix for DECstations

[Allison]

>
>Subject: Re: Ultrix for DECstations
>   From: Paul Koning <pkoning at equallogic.com>
>   Date: Thu, 10 Nov 2005 13:17:36 -0500
>     To: cctalk at classiccmp.org
>
>>>>>> "Patrick" == Patrick Finnegan <pat at computer-refuge.org> writes:
>
> Patrick> No, those were "DEC 3000"s.  DECstations (3000/5000/etc)
> Patrick> were all MIPS.
>
> Patrick> And, from what I've heard, at least one reason that DEC made
> Patrick> Alpha, and didn't port VMS to the MIPS architecture, is
> Patrick> because they'd have to make a lot of changes to VMS, because
> Patrick> of its security model, in order to make it work with MIPS.
> Patrick> Aparently, MIPS just didn't work enough like a VAX CPU to
> Patrick> easily port VMS to it.
>
>Maybe.  But I wonder what could be missing that Alpha has and MIPS
>doesn't that is so critical.

An advantage over VAX.  At that point in time it was considered but 
the forward planning people already had strong feeings that the VAX
killer machine was to be next generation and generally that meant
larger address (more than 32bits).

>Supposedly, the only reason MIPS has supervisor mode is that DEC
>insisted on having it added.

I'd heard that.  Never able to verify it.

Allison