On 14-08-30 05:15 PM, Alan Stern wrote:
On Fri, 29 Aug 2014, Matthew Dharm wrote:
Is there an 'easy' way to override the detected size of a storage
device from userspace? If we had that, someone could write a helper
application which looked for this particular fubar and try to Do The
Right Thing(tm), or at least offer the user some options.
You mean, force a Media Change event and override the capacity reported
by the hardware? I'm not aware of any API for doing that, although it
probably wouldn't be too hard to add one.
How would the user know what value to put in for the capacity? Unless
the drive had been hooked up to a different computer and the user
manually noted the correct capacity and typed it in, it would have to
be guesswork.
Might another possibility be using the SAT layer to issue
the appropriate ATA command via the SCSI ATA PASS-THROUGH
(12 or 16) command to find out the disk's size. This might
be a possible strategy if READ CAPACITY(10) yields 0xffffffff
for the last sector's LBA and the follow-up READ CAPACITY(16)
fails or yields a truncated value.
Doug Gilbert
BTW Been looking at a USB-to-SATA adapter that uses the
UAS(P) transport. I thought nothing could have worse
SCSI compliance than USB mass storage devices. I was
wrong ...
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