Review/Test: Pseudo-device unit number management patch

[M. Warner Losh]

In message: <20040219025604.D76134 at alpha.siliconlandmark.com>
            Andre Guibert de Bruet <andy at siliconlandmark.com> writes:
: The likes of ATA disks include serial numbers in words 10-19. These could
: be used to positively identify a drive when its availability has come
: into question. From what I recall, CF cards use an ATA-like command set.
: Wouldn't it be possible to get the serial number and model from them for
: positive identification?

Not when I tried it a few years ago.  The serial numbers were all 0 at
the time (at least on the brands of parts I was messing with).  Things
may have changed since then.  And that's not a property of the
controller, but the disk connected to the controller, which starts to
get messy from a layering point of view.  Besides, you'd have to keep
a history around for a 'while' of what the unique key was, and that
has other issues if you are inserting lots of different CF into a
machine (say to create bootable CF for production).

Warner