Here is the picture:
- every time i'm trying to unmount my /dev/hda5 (vfat partition) it says that the device is busy.
- I have commented out its entry in /etc/fstab
- after that I restarted my PC so /dev/hda5 would not be mounted
- then mounted it manually using this line: mount -t vfat /dev/hda5 /windows/fat
- it mounted perfectly fine, but I can't unmounted. It says device is busy, just like when it's mounted using fstab.

I also made sure that when I do unmount I am not in /windows/fat, there for this partition is not being used at the moment of umount.

Any ideas of what could be wrong?

I'm using FC4 by the way.

Thank you in advance.

Perhaps try
# lsof /dev/hda5
to find out what is still using the device.

I had a very similar prblem with CD/DVD discs on Fedora Core 3. Every time I tried to unmount and then open the tray, I got an error saying it was busy. I eventually figured out that if I just used the eject command instead - it worked. I never really did figure out what was wrong, hoever I would be willing to bet while clearly not the same trouble, probably related. Also I'm working mounting a bunnch of different drives in Fedora Core 4 right now (on my Dell Laptop, my NTFS partition and an NTFS USB Drive) and was able to follow / modify this gentleman's instructions for my needs: http://www.mjmwired.net/resources/mjm-fedora-fc4.html
I have found his guide pretty invaluable in assiting me with minor annoyances on my machine.

I ran the lsfo command and this is what it gave me:
COMMAND: gam_serve
PID: 2825
USER: vitali
FD: 15r
TYPE: DIR
DEVICE: 3,5
SIZE: 4096
NODE: 902
NAME: /windows/fat/.Trash-vitali

This is not extactly how it appeared, which was in a nice table.

Any way, I decided that maybe I should delete .Trash-vitali and then I ran lsof /dev/hda5 again.
After that I got this out put.
gam_serve 2825 vitali 15r DIR 3,5 4096 902 /windows/fat/.Trash-vitali (deleted)

I still was not able to unmount.
So i decided to kill gam_serve. Every time I kill it, it would just get new PID. By the way its PPID is 1 so I assume it belongs to init.

a quick google search found this:

http://www.security-forums.com/forum...734f20da0cb69e

I believe it will probably relate and solve your issue.

I too searched google, for results like:
http://www.redhatforums.org/ftopic3333.html

The bug report:
https://bugzilla.redhat.com/bugzilla....cgi?id=142637

Configuring gamin:
http://www.gnome.org/~veillard/gamin/config.html

so, either:
# killall -9 gam_server; eject /media/cdrecorder
or
upgrade gamin to 0.0.25 (system update)

I just mounted vfat parttion again the same way I was doing it and then I was able to unmount it with no problem with out killing "gam_serve". Now i 'm just confused.
I took a look at this links you guys posted and they give a good insight on the problem.

So I think I'll update my "gam_serve" if this problem appears again, since killing it was not solving the problem before.

Thanks for you time guys. I'll keep playing with that partition.

AFAIK gam_serve(r?) is a gamin process.
ie. upgrade gamin
one of those posts suggests that doing a normal system upgrade
will fix the problem (although I think that was for FC3)