Boot problem: "ata0: resetting devices"

Kent Stewart kstewart at
Fri May 30 10:04:41 PDT 2003

On Friday 30 May 2003 09:50 am, Rich Morin wrote:
> At 7:29 AM -0700 5/30/03, Kent Stewart wrote:
> >I use the Promise TX2 and Maxtor pci cards in several systems. I
> >just dropped them in and they worked. You would have to boot scsi.
>                                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> So, you're saying that I can't boot from an ATA drive on a PCI-based
> controller card?  What is the background for this limitation?

No, you didn't understand. The ATA cards appear like a scsi to the bios. To 
boot from an add in ATA card, you have to choose scsi boot.

> Also, I'm curious about the effects of turning off hw.ata.ata_dma;
> outside of using some CPU time, what are the likely effects of this.
> For instance, is this likely to slow down disk transfers, assuming
> that the system is mostly idle?

You lose a lot of speed. My new ATA cards are all UDMA-133. Dma transfers are 
always faster. PIO is set at something like 16MB/s. You only get so many 
milliseconds of time for a each transfer block and dma is always faster.


Kent Stewart
Richland, WA

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