[TUHS] Device special files
Dave Horsfall
dave at horsfall.org
Wed Feb 7 15:39:08 AEST 2018
On Tue, 6 Feb 2018, Bakul Shah wrote:
>> Wasn't that "devfs" (which Penguin/OS calls "udev")? I've never
>> grokked that concept.
>
> In the old days where a limited types of devices were
> available for a particular kind of machine, they could be
> statically assigned a major dev number (matching their index
> in the {b,c}devsw table). To make them accessible to users you
> did
>
> mknod <name> <b or c> <major> <minor>
[...]
Umm, I've known that since Edition 5; I'm not exactly new to Unix, you
know...
[...]
> So the point of devfs is to avoid having to do mknod manually and yet
> provide access to all found devices from the userland. As a side effect
> you can also use it for programs that run in their own sandbox or for
> jails and require access to a device.
That makes sense; bit of a pain when a USB device suddenly disappears just
I unplugged it, though...
--
Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."
More information about the TUHS
mailing list