RE: Large disk drives

[David Laight <David.Laight-ZS65k/vG3HxXrIkS9f7CXA@public.gmane.org>]

From: Norman Diamond
...
> By the way, I've seen some USB bridges that lie about whether they
> performed various SAT commands (ATA passthrough), but told the truth
> about performing an ATA IDENTIFY DEVICE through SAT.  So we could attempt
> ATA passthrough with an IDENTIFY DEVICE command, and if it happens to
> return a sane looking result, we could comparre it to the bridge's own
> translation of READ_CAPACITY_10 and READ_CAPACITY_16.  If the passthrough
> yielded a sane result and the capacity doesn't match, we know not to
> trust the bridge with 16-byte commands (except if tested, as mentioned).
> In such a case, we don't even have to look at the partition table.  Of
> course if the ATA passthrough fails or if the result is garbage then
> abandon this test and maybe look at the partition table.
...

Don't count on devices answering ATA IDENTIFY correctly either.
I had some CF cards from one of the main 'labels' that reported
an incorrectly layed out identify response, and 2 others (almost
identical) that locked solid when the request was issued.
We tried to send them back, but they were returned with a nice
shiny new MBR table.

	David



--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html