Re: blacklist of hard drives that misreport serial numbers

[Ethan Baldridge <baldridge.ethan@gmail.com>]

Thanks, David,

On Fri, 2010-06-11 at 18:38 -0400, David Zeuthen wrote:
> Hey,
> 
> On Thu, Jun 10, 2010 at 11:57 PM, Ethan Baldridge
> <baldridge.ethan@gmail.com> wrote:
> > Thanks for the info, David, but unfortunately these are USB drives, and
> > scsi_id doesn't seem to return anything (although this is with udev
> > version 147, so I can try upgrading, but that patch only seems to affect
> > the scsi subsystem - has something similar been done to usb?)
> 
> I think that we always use the USB serial number for any device
> connected via USB. I remember something about that if the USB device
> is a ATA disk and the bridge is sufficiently compatible, it should be
> possible to retrieve the ATA serial number from IDENTIFY data.
> Presumably it's a simple matter of attempting to run ata_id (which I
> don't think we currently do).
> 
> Try checking the devices with ata_id (from udev), hdparm(8) and
> skdump(1) and check if the serial reported by them is what you're
> after?
> 

ata_id returns nothing for any of the USB drives.
hdparm also gives nothing for any of them except:
 HDIO_DRIVE_CMD(identify) failed: Invalid exchange
 HDIO_GET_IDENTITY failed: Invalid argument

skdump gave much more interesting results.

For the Seagate drive (which is already returning the "proper" - or at
least expected - serial number) it gave a whole battery of SMART data,
as well as Model: [ST3500820AS], and Serial: [5QM0A7X7]

For the Toshiba drives (which do not have the expected serial number) I
only got:
$ sudo skdump /dev/sdg
Device: sat12:/dev/sdg
Type: 12 Byte SCSI ATA SAT Passthru
Size: 305245 MiB
Awake: Operation not supported
ATA SMART not supported.

So it seems like that's also a dead-end. I think these drives just don't
give useful information to the operating system. Of course, you can
disagree and say that in reality they don't have useful information
printed on them, but either way it comes down to the same thing as far
as I can see - "don't buy these if you care what the serial number is."

The drives are the pocket-size ones in a solid molded enclosure with no
way to get at the actual drive, so it's definitely not helpful to know
that *if* I could take it apart and look at the drive, it *might* have
the number I want printed on it. Toshiba should really put that on the
outside (as Seagate apparently does, at least for one model.)

Thanks,
Ethan