View Source: DevFs - Waikato Linux Users Group

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__devfs__ is the Device FileSystem. It's optional starting with LinuxKernel 2.4 and not recommended with LinuxKernel 2.6 as it has been deprecated in favour of SysFs and [UDev].

It was designed so that instead of having to have a central body allocate major and minor numbers (unique identifiers) to devices, you could access them more like a namespace. For example, your serial port /dev/ttyS2 would become /dev/tts/2; console /dev/tty3 would become /dev/vc/3. You could still have support for the old names for software that would otherwise be confused by these changes.

You can find a detailed description of <tt>devfs</tt> at http://www.atnf.csiro.au/people/rgooch/linux/docs/devfs.html.

<tt>devfs</tt> was abandoned for a number of reasons: there were problems with its implementation in the kernel which nobody was prepared to fix, and it enforced a particular device-naming policy, which many people felt was not something that the kernel should be doing.

<tt>udev</tt> by contrast, runs in userspace and can be extensively controlled by the user through its configuration files. Management of device special files is kept separate from information about the hardware; the latter is made available by the kernel through <tt>sysfs</tt>.

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Last edited on Monday, June 25, 2007 12:47:49 pm by LawrenceDoliveiro

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