Busses

Old machines had their own busses

* SBUS on Sun, Podule on Archimedes

* Big job porting

New machines have standard busses

* PCI, USB

Standard busses make things:

* Cheaper: Use commodity boards on other systems (e.g. Alpha)

* More open: Often one chip soloutions (PCI in, SCSI out) - just find out about the chip

* Easier to port: Drivers for PCI cards on one system usually work on others

Teach Linux how to talk to the bus on that architecture