jgarzik at pobox.com
Thu Aug 12 22:08:25 PDT 2004
* From the T10 Reflector (t10 at t10.org), posted by:
* Jeff Garzik <jgarzik at pobox.com>
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,
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