On Tue, 16 May 2000, emanuel stiebler wrote:

> From: Toru Nishimura <nisimura@itc.aist-nara.ac.jp>
> 
> > Rather sane and attractive solutions (a.ka. pipe dreams) for DECstation
> > CPU daughter cards would fit in;
> >
> >     - RM 5200             "nicer than original R5000"
> 
> I thought about that long before. Problem is the "legal" stuff. With a
> different CPU, you have to make changes in the monitor EPROMs. You're not
> allowed to do this. So you have to write a new one with all the stuff in it,
> what is needed (debug/tftp/mop/...)

As long as we're talking pipe dreams...

	What about a 'helper' ROM on the daughter card that does any CPU
specific setup so that the motherboard ROMS work as-is... The daughter
card could also have local SDRAM.

	I guess the hardest part would be re-creating the
MIPS-BUS-->TC/MEMORY ASIC. Might be possible to use the old ASIC with a
newer processor as long as the CPU BUS was the same (or very similar) and
could be slowwed during ASIC accesses...

	Well... back to the real world...

> 
> > SGI made very fine product line of Indigo/Indy/Indigo2.  They kept the
> > original Indigo design long time swapping/upgrading processor modules
> > repeatedly.  It's shame Digital abandoned nicely competetive desktop
> > solutions of MAXINE and 3MAX+ in favour of earlier introduction (heaty)
> > 21064.
> 
> I'm sure, we would seen nice DS with even MIPS 5000/8000/10000, IF the alpha
> would be delayed. But they finished the alpha design, and prefered to sell
> their own CPU.
> 
> cheers,
> emanuel
> 
> 
> 

Peter Wallace
Mesa Electronics