> From owner-port-sparc@NetBSD.ORG Wed Sep  6 13:26 PDT 1995
> Date: Wed, 6 Sep 1995 14:14:18 -0400 (EDT)
> From: Aaron Brown <abrown@eecs.harvard.edu>
> X-Sender: abrown@muscato
> To: Aleksi Suhonen <ams@lenkkari.cs.tut.fi>
> Cc: Paul Kranenburg <pk@cs.few.eur.nl>, port-sparc@NetBSD.ORG
> Subject: Re: bootstrapping a sun4m 
> Mime-Version: 1.0
> X-Loop: port-sparc@NetBSD.ORG
> 
> On Wed, 6 Sep 1995, Aleksi Suhonen wrote:
> 
> >  
> > }-But the sun4m port is actively being worked on and there has been some
> > }-substantial progress over the past few months.
> > 
> > Out of interest ... What exactly have been proven to be the problems with
> > porting NetBSD (or mach or any other os) to sun4m?
> 
> There have been several large hurdles, mostly due to inadequate 
> documentation and variation between models.
> 


<stuff deleted>

> 
> Finally, there are way too many variants on the 4m architecture. The 
> kernel has to detect and act appropriately for microsparcs, 
> microsparc-IIs, supersparcs, and hypersparcs. Each processor type has 
> different MMU control registers and different memory-fault handling 
> procedures. Also, the supersparc/hypersparc machines (SS10, SS20) use a 
> 36-bit physical address space for accessing I/O, which makes device and 
> sbus support a bit grungy.
> 

Lot's of this can be gotten from the chip manufacturers. Remember TI
and Fujitsu fab some of the chips. You can get doc. directly from the
vendors.

-brad w.