I just learned that one can use "sudo update-pciids" and "sudo
update-usbids" to update the id lists for pcu and usb devices (I am using
ubuntu 9.10).  I also learned that apparently the system is not set up to
automate this in any way.  I've never seen any advice to do so.  Checking it
out, it seems that running the former on this system added a net of around
360 device ids and a bunch of them were video cards (something that people
often do upgrade).

1) As far as I can tell, these device id lists are only used to report to a
human what devices are present (using lsusb, lspci and maybe lshw and such)
and serve no system function.  Can anyone verify that?

2) Can anyone give a brief description of how the system knows what driver
to use for a given device?

3) If the generic answer is too complicated, how about specifically for a
webcam or a 3G modem?

I started looking into this because a friend has a 3G USB connected modem
for his Verizon 3G network connection and wants me to figure out how to use
it in ubuntu.  While researching that I ran across the pci and usb id lists
and checked my HP Pavillion laptop where I've never had much luck getting
the webcam to work though lsusb shows it to be a Ricoh ... Webcam [R5U870].

BTW, I did find https://wiki.ubuntu.com/NetworkManager/Hardware/3G and
https://wiki.ubuntu.com/NetworkManager/Hardware/3G/Probing which may help me
solve his problem but does not answer any of my 3 questions.

-- 
Dazed_75 a.k.a. Larry

The spirit of resistance to government is so valuable on certain occasions,
that I wish it always to be kept alive.
 - Thomas Jefferson