Experimental Physics and
Industrial Control System

Emmanuel Mayssat <[email protected]> · Wed, 02 Jan 2008 11:14:50 -0800

Mark,

>  > I am not a Linux expert by any means. What is the difference between
>  > the /dev and /proc filesystems? 
>  >

/proc is similar to the registry in windows, it used for very low
level/kernel level configuration. You probably don't want to touch that
unless, you really know what you are doing.

/dev is were the device files are located. In Unix, you read from and
write to a device, by reading and writing to a file. If you need more
sophisticated command like "eject cdrom" you use ioctl/or direct system
calls.

Previously /dev files were "static" files, created once and for all.
Because of the number of devices supported by the OS kept on increasing,
that directory became overpopulated. udev is solved the overpopulation
problem of devfs.

With 2.6 kerenls and udev, the creation of the /dev files is done
dynamically when the kernel modules/driver is loaded (kernel modules are
usually loaded at reboot).

So when you load the module, the associated /dev files are created. Now
those files have default settings/rights, which may not be those you
want. If this is the case, you need to configure udev to give the
correct rights to those files. This is done by changing the udev
configuration files in /etc/udev

Good luck,

--
Emmanuel

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System