Subject: Re: VS4000 SCSI: status
To: Anders Magnusson <>
From: Matt Thomas <>
List: port-vax
Date: 03/08/2000 14:33:56
At 01:25 PM 3/8/00 , Anders Magnusson wrote:
> > 
> > I looked at modifying the ncr53c9x to pass the proc but that would involve
> > extensive changes (such more than i would want to make).  I might be able
> > to cheat and only do vmapbuf/vunmapbuf on KA46/KA48/KA49.
> > 
>Yep, that would be simple (until a better solution comes):
>         if (vax_boardtype != VAX_BTYP_49)
>                 return;
>or similar in vmapbuf/vunmapbuf. The quick solution :-)

Exactly my thought.

> > Also today I found out that the KA49 (and related designs) use a slightly
> > different mechanism for their SGMAP.  Since they have a SGEC, they only have
> > a 8192 entry SGMAP in dedicated SRAM.  So the vsbus_dma needs adapt to this
> > difference. 
> >
>Does it have special RAM for it (as the Qbus adapter) or does it use
>the main memory on a special place (as the KA46)?

 From my reading, closer to the Qbus adapter since it has special RAM.
I'll work on the KA49 when I get home.

The only problem i have now is that occasionally the KA46 seems to lose an
interrupt.  Can't seem to figure out why.
Matt Thomas               Internet:
3am Software Foundry      WWW URL:
Cupertino, CA             Disclaimer: I avow all knowledge of this message