Re: RFC: ATA to CAM integration patch

From: Alexander Motin <mav_at_FreeBSD.org>
Date: Mon, 29 Jun 2009 14:23:56 +0300
Ulrich Spörlein wrote:
> On Sat, 27.06.2009 at 12:06:04 -0600, Scott Long wrote:
>> Alexander Motin wrote:
>>> This is not a problem. ATA disks does not have SCSI INQUIRY command. 
>>> They use own IDENTIFY instead. inquiry should work for ATAPI devices, as 
>>> they are SCSI deep inside.
>> This is really the big missing piece in camcontrol; we need to add
>> support for getting the IDENT info and getting/setting various
>> attributes, as well as sending ATA commands over passthrough.
> 
> not sure if this is related, but I always wondered why tools like
> smartctl never work with USB attached ATA disks. Is it missing support
> in our drivers and smartctl or is it simply impossible?

I don't know much about USB storages and protocols used there, but I 
think it is the ATA->SCSI protocol conversion done by ATA->USB adapter 
limits functionality. If this is correct:
http://en.wikipedia.org/wiki/USB_mass_storage_device_class
, it is impossible to avoid this conversion in common case.

-- 
Alexander Motin
Received on Mon Jun 29 2009 - 09:24:07 UTC

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