Re: devfs vs udev, thoughts from a devfs user
From: Chris Friesen
Date: Tue Feb 10 2004 - 14:47:31 EST
Mike Bell wrote:
Why does it make management easier to have no predictable name for a
device?
I believe this is a misconception.
Udev uses standard rules by default. If the end-user (or their distro)
wants to add additional rules or override these rules, they can do that.
I think the space savings are a pretty good reason alone. Add to that
the fact I think devfs would be a good idea even if it cost MORE
memory... You can mount a devfs on your RO root instead of needing to
mount a tmpfs on /dev and then run udev on that.
Don't you have to explicitly mount /dev as type devfs? How is this
different than mounting it as tmpfs?
A devfs gives
consistant names for devices in addition to the user's preferred
user-space dictated naming scheme.
Udev gives consistant names unless you explicitly override it.
A devfs means even with dynamic
majors/minors, even if you have new hardware in your system, your /dev
at least has the devices it needs.
So does udev.
The real gain with devfs is that you don't need to have any userspace
intervention to get /dev/ populated with a baseline set of device nodes.
As long as the udev code is sufficiently robust and compact, I don't
have a problem with needing a userspace daemon. Anyone that *really*
cares about compactness (embedded people, for instance) is going to use
a static /dev tree pruned down to the bare minimum. For everyone else,
the overhead of having udev running should be unnoticeable.
Chris
--
Chris Friesen | MailStop: 043/33/F10
Nortel Networks | work: (613) 765-0557
3500 Carling Avenue | fax: (613) 765-2986
Nepean, ON K2H 8E9 Canada | email: cfriesen@xxxxxxxxxxxxxxxxxx
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