trouble with 'eject' of cdrom, writing cdrom

[John Francis Lee]

Hello,

I have FC3 installed and notice that, although FC3 mounts a cdrom when
inserted into my cdrom reader/writer, it complains when I try to eject
it :
 eject: unable to open `/dev/hdc'

 [jfl at ws8 ~]$ ls -l /dev/hdc
 brw-rw----  1 root disk 22, 0 Dec  1 19:28 /dev/hdc

So I have changed the permissions :
 [jfl at ws8 ~]$ ls -l /dev/hdc
 brw-rw-rw-  1 root disk 22, 0 Dec  1 19:28 /dev/hdc
and now things seem to work.

Yet I have read that the /dev directory is now dynamically populated,
somehow.
Under what conditions is the /dev directory dynamically populated? 
Will I have to reset permissions in the future?

Thanks for any light you might shed on this phenomenon.

-- 
John Francis Lee
1/9-10 Thanon Trairat
Muang Chiang Rai 57000
Thailand