Hello.
I newly compile and install KDE3.2 under mandrake9.2, and find a strange thing. In order to play songs and hear, I change the permission of the files in /dev/sound as rwrwrw, but next time I restart the PC, they come back to rw----. Does mandrake do some magic on them? Really confusing me. May someone tell me why? Thanks.

I havent got a real answer for you but... stuff in /dev are devices that linux adds at boot time, if you really want them to have different permissions than default you need to tell linux to add those devices in a different way.

I doubt however that this is a good solution, probably the problem has something to do with your user not being in the correct group or something.

Perhaps you could try re-installing the card.

I know now the solution may be in the setting of devfs.
Does someone know about devfs and tell me how to edit it so that whoever logging in can own the 'write' permission of these device files just like mandrake-9.2 does?

Is it something you can mount ?

I guess it is not (stupid question ...)

Tony yu:
The following is from Linux Format magazine. It is about DVD drives but the section on /dev may be informative.

From LXF #41, Page 94

As for your DVD/CD question /dev/cdrom will be a symlink to your
actual device, such as /dev/hdc. This link will have been created during
the installation, and it makes no difference to anything if it's a CD-ROM
or a DVD drive actually attached to /dev/hdc.
Your instructions for creating /dev/dvd are slightly skewed, as you only
need to do

ln -sf /dev/hdc /dev/dvd

The kernel doesn't know anything about /dev/dvd, as anything which accesses /dev/dvd will really access /dev/hdc - /dev/dvd is simply a convenient alternative name for the device. If you want to create something in /dev then you either need to make the device with mknod, which is passed a major/minor number which defined the device, along with an entry to define it as either a block device or a character device. Something like a serial port is a character device and a hard drive or CD-ROM drive is a block device. The major/minor is what is used by the kernel to figure out what the device actually is and how to access it. Generally you will not want to use mknod to create devices unless you know what you're doing, but you may want to use ln to create links to specific devices with more useful names such as /dev/mouse, /dev/modem, /dev/zip and so forth.
If you're using devfs, note that when you reboot, any modifications you make within the /dev directory will disappear. You will want to look at /etc/devs, as there are entries in there which allow you to automatically create the symlink when the device is registered the kernel.

When I login as a common user by run-level 3, the permission of the file in /dev is correct meaning I can hear sound, play cd etc. However when logging in by run-level 5, all of the permission are set to root, not to the user I login as. Anyone has an answer? Thanks for your reply in advance.