dev_*:
	Devices. (Please read 'Emulation of hardware devices' in
	doc/technical.html for more information about these.)
	Example: dev_wdc, the IDE/ATA[PI] harddisk controller.

bus_isa.c:
	ISA bus framework. This basically just registers the ISA legacy
	devices that are common to all machines.

bus_pci.c:
	PCI bus framework, and some glue code for PCI devices. Example of
	glue code would be PCI-IDE controllers, which are implemented using
	dev_wdc plus some PCI configuration registers, which identifies the
	specific controller (fake, but it usually works).

other files:
	Misc. stuff.