Path: utzoo!attcan!uunet!cbmvax!jesup
From: jesup@cbmvax.commodore.com (Randell Jesup)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: 2090/st-506 revisited
Keywords: Thanks Dave!!
Message-ID: <15809@cbmvax.commodore.com>
Date: 12 Nov 90 20:01:19 GMT
References: <1990Oct18.035721.2305@cbnewsj.att.com>
Reply-To: jesup@cbmvax.commodore.com (Randell Jesup)
Organization: Commodore, West Chester, PA
Lines: 30

In article <1990Oct18.035721.2305@cbnewsj.att.com> paulm@cbnewsj.att.com (paul.j.maioriello) writes:
>Thanks to suggestions from Dave Haynie, I have gotten the 2090 with
>a CDC WREN st-506 drive to work fairly reliably in my a3000 (it's not
>perfect yet).

>In order to get it to work, it seems you have to get the 32 bit memory
>out of the way.  My first attempt at doing this was to
>use the value 2 for the BufMemType parameter in the mountlist file.
>What I want would like to try doing next is to
>re-enable the 32 bit memory after the partions are mounted.  If I do this
>now, all the problems come back.  Looking through the 3000 documentation,
>page 7-52 tells about all the stuff you can put in your mountlists file.
>It seems to me that a key value is what you put in the Mask parameter.
>THe description states "Address Mask to specify memory range that DMA
>transfers can use".  It seems to me that tweaking this parameter is how
>you can keep DMAs into 32 bit memory from happening.  THe problem is I
>have no idea what value to use.

	Use " Mask = 0x00fffffe".  This restricts DMA destinations to the
low 16M of memory (where the Z-II space is).  That, combined with a CHIP
bufmemtype (which you already figured out) should make the A2090 work on
an A3000.

	We've added a flag to 2.0 to allow Z-II devices to get guaranteed
allocations from 24-bit space, but that doesn't help older drivers.

-- 
Randell Jesup, Keeper of AmigaDos, Commodore Engineering.
{uunet|rutgers}!cbmvax!jesup, jesup@cbmvax.cbm.commodore.com  BIX: rjesup  
Common phrase heard at Amiga Devcon '89: "It's in there!"