[t13] SCSI ATA f/w revision bytes how many

Pat LaVarre p.lavarre at IEEE.org
Thu May 27 18:42:18 PDT 2004


* From the T10 Reflector (t10 at t10.org), posted by:
* Pat LaVarre <p.lavarre at ieee.org>
*
> I think you are missing some context...
> 
> This opcode is used to tunnel through a _fake_ SCSI layer to reach a 
> real ATA device behind it.

That is one purpose, aye.

But this op by definition serves a second purpose well also:

> ATAPI does not come into play here.  This "ata passthru" opcode is only 
> needed for ATA.  For ATAPI, one does not need to pass through a fake 
> SCSI layer, but rather avoid the hardware device's SCSI layer and talk 
> directly to ATA.  Subtle difference... but substantial.

Difference, aye.

For an ATAPI device, the tunneling I want is thru software, not thru
hardware, to ATA thru SCSI.

For example, thru Linux ioctl CDROM_SEND_PACKET or ioctl SG_IO I want to
send ATA op xA1 "IDENTIFY".

Rumour tells me in Linux I can substitute other ioctl to get pass thru
to ATA.  But I haven't found any such trick in Mac OS X, nor in Windows
for ops outside of xEC/A1 until the bleeding-edge Windows Server 2003.

Pat LaVarre


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