RE: stupid SATA questions

From: Aleksey Gorelov
Date: Tue Jun 07 2005 - 17:30:11 EST



>From: linux-kernel-owner@xxxxxxxxxxxxxxx
>[mailto:linux-kernel-owner@xxxxxxxxxxxxxxx] On Behalf Of Jeff Garzik
>Sent: Tuesday, June 07, 2005 11:01 AM
>To: Kumar Gala
>Cc: Linux Kernel list
>Subject: Re: stupid SATA questions
>
>Kumar Gala wrote:
>> These questions were posed to me and I was hoping someone would have
>> better knowledge about the works and usage of SATA then I
>do. All of
>> these questions are around understanding how important the
>performance
>> of PIO mode is.
>>
>> How often would one run in PIO mode? Why would one run in PIO mode?
>
>Never. No idea. :)

Some BIOSes/option ROMs do. Especially SATA RAID ones.
But unless you are using BIOS interrupts...

Aleks

>
>Unless you have a broken device, or a command that cannot work
>with DMA
>(such as IDENTIFY DEVICE), PIO mode is quite pointless. It is
>emulated
>under SATA, turned into FIS's on the SATA bus.
>
> Jeff
>
>
>
>-
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