[t13] T10/04-262r0

[Marushak, Nathan]

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I agree.

-----Original Message-----
From: owner-forum at t13.org [mailto:owner-forum at t13.org] On Behalf Of Jeff
Garzik
Sent: Thursday, August 12, 2004 10:08 PM
To: t10 at t10.org; Forum at t13.org
Subject: Re: [t13] T10/04-262r0

This message is from the T13 list server.



A note regarding PATA<->SATA hardware bridges, and vendor-reserved
commands.


As Nathan M and Pat noted, there is a question of what happens for a 
vendor-reserved ATA command that must traverse a PATA<->SATA bridge.

For those unfamiliar with the current hardware landscape, many early 
SATA host controllers were simply pre-existing PATA solutions with a 
SATA bridge.  I call these "first gen SATA", to distinguish them from 
the non-bridged, usually FIS-based SATA controllers coming out today.

First gen SATA controllers will typically -not- be able to control the 
command protocol associated with a vendor-reserved ATA command.  As I 
noted in my response to Pat, my guess is that the SATA bridges will work

for non-data and PIO[-mult] protocols only, but I have no test results 
to back this up.

PATA controllers and "second generation" SATA controllers shouldn't have

any problem with a vendor-reserved command's protocol requirements, 
however esoteric.

	Jeff