Ruminations on Udev, null and console

alupu at verizon.net alupu at verizon.net
Fri Feb 25 16:07:47 PST 2011


Feb 25, 2011 03:11:51 PM, Bruce Dobbs wrote:

> I haven't looked at this code in quite a while, but I don't
> see these instructions as contradictory.

Hi Bruce,

I commented out 'cp -a /lib/udev/devices/null /dev' in "udev" script.
and did a reboot.
_I_ didn't notice any changes (messages, etc.) in the console log on boot.
Nor in dmesg.
However, it's possible that my basic system differs somehow, somewhere
on LFS boot.

> Newer versions of udev or the kernel may make some of these procedures 
> unnecessary, but they don't hurt anything.
> A device node takes up 1 directory entry and no additional space.

Agreed.
BTW, I didn't say they are "contradictory".  Just
>> redundant (and _misleading_).
Misleading (IMHO) because either use both copies (i.e., _and_
console) or none at all.  Let's not forget, though, I started with
"ruminations", not "complaints" (or some such).

> I don't understand what appears to be a sense of urgency in your post.

No urgency (or sense of it) at all:
>> _finally_ ...
>> this fallacy goes back quite a few iterations from 166.
However, I apologize for the word fallacy.  Way too strong
and misleading:).

> What are the drawbacks of the procedure as is?
None.  It works.  I did express my gratitude to all involved
for their hard work to make our life easier.

---

I do have a confusion underlying this thread.
I have claimed (possibly wrongly), the Udev philosophy assumes a /dev
absolutely empty.  Are the initial ("metal") null and console nodes
an LFS specific requirement (based on its particular boot/log sequence
I tested and confirmed by 2.6.21),
is it "sanctioned" by Udev developers,
and/or a "pure" Udev is supposed to start with /dev really empty?

Thank you very much,
-- Alex



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