I'm using Redhat 9. Kernel 2.4.20-8.

I got a sandisk cruzer micro usb drive, and was able to get it to work brilliantly. As root, I added the following to /etc/fstab:

/dev/sda1 /mnt/flash vfat noauto,user,kudzu,rw 0 0

and I created the mount point:

mkdir /mnt/flash

Then I can mount and umount at will as my non-root user. And I can write files to it and delete files from it, and see those changes when I put the drive on my Windows box. Perfect.

However, after a while (many minutes, or a couple of hours--I haven't timed it), /etc/fstab reverts to the version without my change in it, and the /mnt/flash directory disappears. I haven't tried keeping the device mounted for that length of time to see if that changes anything. But, nonetheless, it seems like something's happening that shouldn't be. Does the system regenerate the /etc/fstab file periodically? Does it not tolerate changes? Is there another way I'm supposed to modify the mount table?

i don't know redhat, so i doubt this reply would really be as useful as it could be, but Mandrake used to use a daemon called msec (used to as in when i last used it before going to gentoo) which did exactly what you're guessing at. when you start up redhat, is there a service referring to security levels? if you edit fstab by hand, and then go into whichever GUI configuration tool redhat currently has, is that change reflected there? maybe look for a backup copy of fstab in etc...
might turn up something....

This page clued me in to something. There's a utility that updates the /etc/fstab file, called updfstab. There are config files that go along with it, namely /etc/updfstab.conf and /etc/updfstab.conf.default. The man page for updfstab says that devices it adds to the /etc/fstab file are marked with the "kudzu" option. I copied the cdrom and floppy partitions when I added the flash mount partition, and included this option without knowing what it did (the mount and fstab man pages don't mention it) (I thought it might tell the desktop manager to automatically create a desktop icon for the volume when it's inserted.).

So, it looks like updfstab was seeing the "kudzu" option for my flash volume and automatically updating /etc/fstab and removing it. Hopefully it was removing /mnt/flash for the same reason, and not because it thinks it owns /mnt, and can delete whatever it wants from there.