[rescue] WTB various U10 stuff

Jochen Kunz jkunz at unixag-kl.fh-kl.de
Mon May 17 17:10:26 CDT 2004

On Mon, 17 May 2004 16:57:03 -0400
"Patrick Giagnocavo +1.717.201.3366" <patrick at zill.net> wrote:

> SATA vs ATA is not the issue.  The issue is sucky drivers.  NetBSD
> probably has better drivers.
I think the real problem is the IDE adapter, not the driver. The U5 /
U10 has the broken and buggy CMD6?? chip, that isn't able to do proper
DMA. So you can transfer only a few words of data per DMA transaction,
resulting in high interrupt load. The DEC PWS 500au has the same chip.
Someone on the NetBSD-alpha list did benchmarks with an IDE disk
connected to the CMD6?? on board adapter and with the same disk
connected via an IDE-SCSI bridge to a Qlogic SCSI adapter. The disk got
much more throughput with less CPU usage when connected via SCSI.


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

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