Mysteries of /dev/eth?

[Timothy Murphy]

I'm puzzled by the device /dev/eth0 , etc,
chosen by different drivers.
This isn't a problem for me, just a mystery.

For example, I just installed Fedora-7 on a laptop
(an old Sony PictureBook - C1VFK)
and when I attached it by ethernet to my LAN,
it immediately worked through /dev/eth0 ,
despite the fact that /etc/modprobe.conf
had an incorrect "alias eth0 orinoco_cs",
while the driver in use is pcnet_cs .

By contrast, on another laptop
although I have the correct "alias eth0 orinoco_cs"
in /etc/modprobe.conf , a strange device -
/dev/dev1375 , IIRC, was used.

So my questions are:

1) How does the machine decide which driver to use; and

2) How does it decide which device to use?

Has it got something to do with udev ?