Can anyone tell me what is wrong? I am running Fedora 1.something.
I can't get my cds out. Nautilus says error device busy.
Even root can't umount them, also gets device busy.
How do I get the cd out, short of reboot?? And I thought root do anything! No supermen anymore??

you're already in the directory that your trying to umount.

not always quite as simple as that, but somethign somewhere on your system is still actively using that directory. don't make the mistake of thinking that this is bad... just think what happens when you take a cd out the drive on windows mid game...

This happens to me, and the problem has a few different causes.

1] I opened a file on the CD, and the program which opened the file from the CD has not released the CD - saving the file to a new home might fix this, but sometimes I need to completely quit the application (and Konquerer was a major cause of this issue, a few releases back).
Ultimately, this falls back to being what acid_kewpie posted, but user caused the situation.

2] I've had some distros that I installed 'automatically' that I eventually learned had no idea of how to set up fstab, so the drive gets mounted through a long twisted method and that keeps the drive status as busy when in reality the mount method is actually lost.
Ultimately, this too falls back to being what acid_kewpie posted, but in this case the distro configuration causes processes that ultimately lost track of drive status.

3] Some ATAPI drives have needed up to 2 or 3 minutes to release the disc from an internal busy status, for some odd conditions of operation. Beats me exactly why, but I'd bet the drives work just fine under Windows, because Windows doesn't care about needing full compliance with any standards.... and Linux uses the standards more thoroughly (I proved this to myself on an ATAPI CDROM that failed miserably in Linux, works fine in Windows).

OK, but it is possible to release the drive somehow, as all filesystems are umounted on shutdown. But that is after all processes are killed I suppose, so that nothing has a lock on it anymore. Is there some way to find out who or what program is actively accessing the CD and or blocking it?
Why can't root do it? I thought he/she could do anything!

lsof | grep 'cdrom'
change cdrom to whatever device your cdrom is
you can then use ps <processid> to see what program is using the device

fuser is also useful.

You say you think root should be able to do that... it's not having certain permissions, it's about not being allowed to do something that will actively crash your system. it's a dumb thing to be able to do.

Just one more thing:
This is using Fedora, 2.4.22 kernel if that is relevant:
I put a music cd in (Fanfare Ciocarlia if you know it, Rumanian) It plays fine. I stop it, try to mount it. Can't.
The cd player can see it, tells me how many tracks. But it can't be mounted : unknown file system. Why is that? I suppose other music cds react the same, haven't actually tried. If it plays, mustn't it be mounted? Or can it play without being mounted?

you can not mount an audio cd, there is no file system to mount. but windows can do it... no it can't, it's just pretending.

Don't want to get on your nerves, so ignore this if you can't be bothered, but how the f does an audio cd work under Linux unmounted. Everything in Linux is mounted under /, one big tree, so I read. Or does the sound card talk straight to the CD, without the intervention of the CPU?
Something is being read. With track numbers and so. Is that not a file system?

Players like Kcd that do not use digital audio extraction do not read audio data. The drive itself decodes the digital audio data back to sound. The player just starts and stops the drive and other type functions. I do not know the process by which it reads the control data but it is not layed out like a disk filesystem. Using these players you need an audio cable connected between the drive and the sound card.

xmms and others including Windows Media player (XP and W2K) use digital audio extraction where the sound info is extracted from the control info. With these players you do not need the sound cable.

http://www.pcguide.com/ref/cd/formatCDDA-c.html

There is a module audio files called cdfs but again I do not know much about it.

You can also try "umount -l <device>". That's a "lazy" umount, so the disposal of processes using the device is deferred until later, after the device is unmounted. I noticed that option one rainy day whiling away my time reading man pages.

I have had this trouble with Fedora Core 1. It is definately an issue under FC1 and was not an issue under RH9.

The only way I managed to fix this was:

ps -aux to get the list of running apps and kill off a few later kmount(?) related items using:

kill xxxx (xxxx is process number)

I don't have the process list handy so I can't remember exactly what they were called but ps -aux lists the processes in order so you get an idea of which ones they might be.

Fedora seemed to let go after that.

FWIW (OT) an audio CD can be fake 'mounted' (like windows mounts it) by using Konqueror and proper URL syntax (there is an entry in KDEs help system but I forget where)..... users can also rip that way as well!

Back onto the topic: I think the unknown filesystem message has to do with some process which your WM has set to run as default but without user knowing about it (Kmount sounds correct to me), and thus the process is not known by you to be locking up the drive.... That automatic thing is a weak or misconfigured attempt at gaining 'automagic' mounting of CDs/Floppies, etc. If I were you, I'd get rid of Fedora Core 1. I used it, it stunk (IMO), and I'm running SuSe 9.0 and loving every minute of it!

If you ever end up with Nautilus not releasing a device.. If after killing Nautilus it just restarts with the same session information. Go into your session manager and set nautilus to not automatically restart.. (trash can icon) remove it. and click apply.. You should see all processes are free on that device.. umount/eject like normal and go to a terminal >> type nautilus to restart it..

I had the same problem with fedora core 2, the process that automatically updates the nautilus windows, for example if you are browsing a directory and with an other prgram save a file to that directory the file automatically appears in the file browser window its that process which is still accessing the cd drive. unfortuanatly I can't remember what the deamon is called, I do know however it is run under xinetd.