linux.conf.au 2003
Example - pcihpfs

                     /proc/bus/pci/slots/
                     |-- slot3
                     |   |-- adapter
                     |   |-- attention
                     |   |-- cur_bus_speed
                     |   |-- latch
                     |   |-- max_bus_speed
                     |   `-- power
                     |-- slot4
                     |   |-- adapter
                     |   |-- attention
                     |   |-- cur_bus_speed
                     |   |-- latch
                     |   |-- max_bus_speed
                     |   `-- power
                     |-- slot5
                     |   |-- adapter
                     |   |-- attention
                     |   |-- cur_bus_speed
                     |   |-- latch
                     |   |-- max_bus_speed
                     |   |-- power
                     |   `-- test
                     `-- slot6
                         ...