The PCI standard has become the de-facto standard for system buses.

Linux provide extensive support for PCI, and contains numerous drivers for network, storage and 3rd party adapters.

The Linux kernel represents PCI devices as pseudo-devices in the sysfs file system:

ls -la /sys/bus/pci/devices

returns:

total 0
drwxr-xr-x 2 root root 0 Jan 29 03:47 .
drwxr-xr-x 5 root root 0 Jan 29 03:47 ..
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:00:00.0 -> ../../../devices/pci0000:00/0000:00:00.0
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:00:00.2 -> ../../../devices/pci0000:00/0000:00:00.2
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:00:01.0 -> ../../../devices/pci0000:00/0000:00:01.0
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:00:01.2 -> ../../../devices/pci0000:00/0000:00:01.2
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:00:02.0 -> ../../../devices/pci0000:00/0000:00:02.0
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:00:03.0 -> ../../../devices/pci0000:00/0000:00:03.0
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:00:03.1 -> ../../../devices/pci0000:00/0000:00:03.1
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:00:04.0 -> ../../../devices/pci0000:00/0000:00:04.0
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:00:05.0 -> ../../../devices/pci0000:00/0000:00:05.0
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:00:07.0 -> ../../../devices/pci0000:00/0000:00:07.0
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:00:07.1 -> ../../../devices/pci0000:00/0000:00:07.1
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:00:08.0 -> ../../../devices/pci0000:00/0000:00:08.0
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:00:08.1 -> ../../../devices/pci0000:00/0000:00:08.1
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:00:14.0 -> ../../../devices/pci0000:00/0000:00:14.0
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:00:14.3 -> ../../../devices/pci0000:00/0000:00:14.3
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:00:18.0 -> ../../../devices/pci0000:00/0000:00:18.0
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:00:18.1 -> ../../../devices/pci0000:00/0000:00:18.1
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:00:18.2 -> ../../../devices/pci0000:00/0000:00:18.2
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:00:18.3 -> ../../../devices/pci0000:00/0000:00:18.3
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:00:18.4 -> ../../../devices/pci0000:00/0000:00:18.4
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:00:18.5 -> ../../../devices/pci0000:00/0000:00:18.5
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:00:18.6 -> ../../../devices/pci0000:00/0000:00:18.6
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:00:18.7 -> ../../../devices/pci0000:00/0000:00:18.7
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:01:00.0 -> ../../../devices/pci0000:00/0000:00:01.2/0000:01:00.0
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:02:03.0 -> ../../../devices/pci0000:00/0000:00:01.2/0000:01:00.0/0000:02:03.0
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:02:04.0 -> ../../../devices/pci0000:00/0000:00:01.2/0000:01:00.0/0000:02:04.0
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:02:05.0 -> ../../../devices/pci0000:00/0000:00:01.2/0000:01:00.0/0000:02:05.0
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:02:08.0 -> ../../../devices/pci0000:00/0000:00:01.2/0000:01:00.0/0000:02:08.0
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:02:09.0 -> ../../../devices/pci0000:00/0000:00:01.2/0000:01:00.0/0000:02:09.0
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:02:0a.0 -> ../../../devices/pci0000:00/0000:00:01.2/0000:01:00.0/0000:02:0a.0
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:03:00.0 -> ../../../devices/pci0000:00/0000:00:01.2/0000:01:00.0/0000:02:03.0/0000:03:00.0
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:04:00.0 -> ../../../devices/pci0000:00/0000:00:01.2/0000:01:00.0/0000:02:04.0/0000:04:00.0
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:05:00.0 -> ../../../devices/pci0000:00/0000:00:01.2/0000:01:00.0/0000:02:05.0/0000:05:00.0
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:06:00.0 -> ../../../devices/pci0000:00/0000:00:01.2/0000:01:00.0/0000:02:08.0/0000:06:00.0
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:06:00.1 -> ../../../devices/pci0000:00/0000:00:01.2/0000:01:00.0/0000:02:08.0/0000:06:00.1
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:06:00.3 -> ../../../devices/pci0000:00/0000:00:01.2/0000:01:00.0/0000:02:08.0/0000:06:00.3
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:07:00.0 -> ../../../devices/pci0000:00/0000:00:01.2/0000:01:00.0/0000:02:09.0/0000:07:00.0
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:08:00.0 -> ../../../devices/pci0000:00/0000:00:01.2/0000:01:00.0/0000:02:0a.0/0000:08:00.0
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:09:00.0 -> ../../../devices/pci0000:00/0000:00:03.1/0000:09:00.0
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:09:00.1 -> ../../../devices/pci0000:00/0000:00:03.1/0000:09:00.1
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:0a:00.0 -> ../../../devices/pci0000:00/0000:00:07.1/0000:0a:00.0
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:0b:00.0 -> ../../../devices/pci0000:00/0000:00:08.1/0000:0b:00.0
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:0b:00.1 -> ../../../devices/pci0000:00/0000:00:08.1/0000:0b:00.1
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:0b:00.3 -> ../../../devices/pci0000:00/0000:00:08.1/0000:0b:00.3
lrwxrwxrwx 1 root root 0 Jan 29 03:47 0000:0b:00.4 -> ../../../devices/pci0000:00/0000:00:08.1/0000:0b:00.4