Subject: Re: Quadra 840AV scsi DMA
To: Mike Haertel <firstname.lastname@example.org>
From: Reinier Jonker <email@example.com>
Date: 04/08/2002 14:38:59
On monday, april 8, 2002, at 11:15 AM, Mike Haertel wrote:
> I have a Quadra 840AV that I have recently set
> up with NetBSD/mac68k. Supposedly the SCSI controller
> on this machine was one of the fastest ever put on
> a 68k mac. However, it is dog slow under NetBSD.
I recognize the problem, Allen Briggs has already explained it.
It is seriously slow
> Is anybody already working on this? If not, I would
> like to take a crack at it.
I don't think so.
> My first thought is to disassemble the SCSI driver
> in the Macintosh ROM to find out how to operate the
> DMA controller. I have MacsBug, and I also have a
> very complete looking table of ROM entry points (from
> the MPW-GM distribution which is freely downloadable
> from Apple). MacsBug has some capability of doing
> symbolic disassembly, but I haven't been able to
> figure out how to get my symbol table of the ROM
> into MacsBug. Anybody know how to do this? If not,
> any other suggestions on how I might proceed?
I'd be happy to help you:
- I have a Quadra 840AV, with two SCSI drives, running NetBSD-current
- I have a current MPW on my G4, including ROM maps
- I have a ROM rip from the machine
- There's a current /usr/src on my Quadra
- My C knowledge is reasonable, my experience isn't :-)
- I have no experience in writing OS code
Please mail me if there's anything I can do.
I do agree this is something that needs work.