Red Hat LINUX 7.2 Reference Manual page 81

Section 4.3:Directories in /proc
4.3.2 /proc/bus
This directory contains information specific to the various busses available on the system. So, for
example, on a standard system containing ISA, PCI, and USB busses, current data on each of these
busses is available in its directory under /proc/bus.
The contents of the sub-directories and files available varies greatly on the precise configuration of
your system. However, each of the directories for each of the bus types contains at least one directory
for each bus of that type. These individual bus directories, usually signified with numbers, such as
00, contains binary files that refer to the various devices available on that bus.
So, for example, a system with a USB bus but no USB devices connected to it has a /proc/bus/usb
directory containing several files:
[root@bleach /]# ls -l /proc/bus/usb
total 0
dr-xr-xr-x
-r--r--r--
-r--r--r--
[root@thoth /]# ls -l /proc/bus/usb/001
total 1
-rw-r--r--
[root@bleach /]#
The /proc/bus/usb directory contains files that track the various devices on any USB busses, as
well as the drivers required to utilize them. The 001 directory contains all devices on the first (and
only) USB bus. By looking at the contents of the devices file, we can see that it is the USB root
hub on the motherboard:
[root@bleach /]# cat /proc/bus/usb/devices
T: Bus=01 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#=
B: Alloc=
D: Ver= 1.00 Cls=09(hub
P: Vendor=0000 ProdID=0000 Rev= 0.00
S: Product=USB UHCI Root Hub
S: SerialNumber=d400
C:* #Ifs= 1 Cfg#= 1 Atr=40 MxPwr=
I: If#= 0 Alt= 0 #EPs= 1 Cls=09(hub
E: Ad=81(I) Atr=03(Int.) MxPS=
[root@bleach /]#
4.3.3 /proc/driver
This directory contains information for specific drivers in use by the kernel.
1 root root
1 root root
1 root root
1 root root
0/900 us ( 0%), #Int=
) Sub=00 Prot=00 MxPS= 8 #Cfgs=
0 May 3 16:25 001
0 May 3 16:25 devices
0 May 3 16:25 drivers
18 May 3 16:25 001
1 Spd=12
0, #Iso= 0
0mA
) Sub=00 Prot=00 Driver=hub
8 Ivl=255ms
MxCh= 2
1
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