[Novalug] /dev question
plarsen at famlarsen.homelinux.com
Tue May 27 12:58:11 EDT 2008
Charles M Howe wrote:
> When I do ls /dev, I see several hundred short files of one type (and a
> handful of of other files of another type). Although I will not claim to
> have burned the midnight oil researching this question, I have spent a
> non-trivial amount of time on it but have been unsuccessful. What gives?
Those are actually not real files. They're "nodes" or rather the
physical access to the devices on your computer. Each node has what's
called a major and a minor number. It's by those, programs talk to
hardware. The kernel sees all devices as such - and presto you have a
"file system" that represents your devices.
In the "old days" we had to have a entry/node in /dev/ for each
potential device we might have. That's a LOT of nodes. As more and more
hardware is added that really because a problem; in some distributions
today you'll find "udev" determining what nodes to create by doing a
system probe on boot. The /dev/ is now a "ram disk" of a kind and you no
longer have to manually create entries to access new partitions, disks
There's a long lived and still used naming convention on the /dev/
volume. http://en.wikipedia.org/wiki/Device_node gives you a good run
down of the /dev/ file system and the types of nodes.
> Charlie the Perpetual Newbie
Welcome to the world of discovery :)
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