(brought back onlist)
Another example, USB again...
A lot of devices are very difficult to
distinguish from another, e.g.
EPSON has the same USB ID's for a lot of printer models and you need to
query the printer information with a vendor specific protocol
Has the situation changed? Isnt the 'serial no.' you mention the same as the
USB ID discussed above?
Ok, so it doesn't work for all USB devices. Mice are probably the same.
Anything with a filesystem or a unique serial, or MAC address, etc,
however is fine. So, ok, multiple identical printers are probably a
problem. At this point you might have to resort to "get different
printers", or "leave them plugged into the same USB port, perhaps on an
external HUB", or "buy an external print server that does ethernet -> USB.
In terms of sound cards, you could use the PCI ID to define the order
in which sound cards are brought up. This doesn't change - or it
shouldn't change, unless you have faulty/crazy hardware - unless you
shift the physical slot the device is plugged into.
 or anything, even including USB devices as long as you are prepared
to put them on the same port every time. Use the USB *bus* ID in that
case, not the PCI ID, obviously :)