I'm a little confused as to how enumeration is accomplished. Specifically, I brought up a system on an old Ampro 
Littleboard 800, and the network interfaces were not identified automatically. I could see that the devices were 
correctly identified in /etc/system/enum/devices/net. I looked in /etc/system/enum/common, and I noticed that while it 
contained the lines:

  enumerator(pnpbios)
  enumerator(usb)

it did not seem to mention pci, so I naively added the line:

  enumerator(pci)

and now the devices are properly identified. That seems fairly straightforward, but begs the question:

Why isn't enumerator(pci) in there by default?

So I went and looked at my development system and an older 6.3.2 system, and both of those systems had PCI-based 
ethernet devices which are identified at boot-up and they do not have the enumerator(pci) in their common file. So how 
are those devices identified?

Any illumination would be most welcome.