Subject: Re: IDE controller card for PWS
To: None <port-alpha@NetBSD.org>
From: Jochen Kunz <jkunz@unixag-kl.fh-kl.de>
List: port-alpha
Date: 08/15/2003 10:07:04
On 2003.08.15 07:59 Wilko Bulte wrote:

> But why aren't you using the onboard IDE controller?
> Not the fastest in the world but..
Not the festest is very kind. The CMD646 in the PWS has a broken DMA
implementation. It can only transfer a few bytes per DMA, so it
generates lots of interrupts. Someone posted benchmarks to this list a
while ago. He compared a quite recent IDE disk connected to the onboard
IDE controller and the same disk connected to the QLA1040 SCSI card via
an IDE-SCSI bridge.=20
pure IDE: high CPU load, small disk throghput=20
IDE-SCSI: small CPU load, high disk throghput=20

So I would recommend: Use a IDE disk with IDE-SCSI bridge on a SCSI
adapter or a DMA capable IDE adapter. If SRM don't like the later
connect a small, old IDE disk to the internal IDE adpter just for
loading the kernel. All actual file systems can be on the new IDE
adapter.=20
--=20


tsch=FC=DF,
       Jochen

Homepage: http://www.unixag-kl.fh-kl.de/~jkunz/