Getting hard drive serial number from USB devices

[Madison Kelly]

Lennart Sorensen wrote:
> On Sat, Jan 14, 2006 at 02:29:35PM -0500, Madison Kelly wrote:
>> Peter wrote:
>>> lsusb -v|...|grep iSerial
>> Thanks for the reply!
>>
>>   Unfortunately, that only gives the serial number of the USB 
>> controller, not the hard drive itself. This is a problem because I use 
>> USB drives with removable disk carriers. If I rely on the USB/IDE ASIC's 
>> serial number my program would not be able to tell the difference 
>> between different hard drives connected through the common carrier.
> 
> What filesystem do you format the drives with?
> 
> If you use ext2/ext3 you can do this:
> tune2fs -l /dev/sda1 |grep UUID
> 
> There are probably similar things you can do on other filesystems.
> 
> Each filesystem is assigned a unique id, which is a very reliable way to
> identify a drive.  If you reformat it, the ID changes of course, but at
> that point it is a new filesystem and hence would have none of the old
> data anymore.
> 
> Len Sorensen

   Currently I use the 'UUID' of a partition as assigned by 'blkid' and 
that works fine with a few exceptions. Those exceptions are the cases I 
am trying to work around. Specifically;

- The UUID of a permission changes if that partition is reformatted.
- No UUID is assigned to some file systems (ie: NTFS).
- On some file systems 'blkid' assigns a generic '0000-0000' UUID (ie: 
'vfat' on digital cameras).

   Being a backup program I want to, ideally, support all file systems. 
This is why reading the serial number would be so ideal; I could create 
a (slightly modified) MD5 hash of the drive's serial number + 
partition/slice number to create a file system agnostic, portable ID.

   If I *can't* get the serial number over a USB interface (as seems to 
be the case now), then I need to find another method to uniquely 
identify a physical disk. The problem is, often people who use my 
program will buy a bunch of disk drives at once, often only in a series 
of serial numbers. So relying on things like the model number or date 
code would also be troublesome.

   Gah!

   Why couldn't disk drive manufacturer's put a small sector or two 
aside with the information always available and outside the view of the 
rest of the disk space? That would be sooooo nice!

Madison

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