I'm having some trouble with sharing a partition between Ubuntu and Vista RC2. Basically, my disc looks like this:
/dev/sda1: 100 GB NTFS partition, contains windows
/dev/sda2: 10 GB FAT32 part, holds all my music
/dev/sda3: 84.5 GB ReiserFS partition, contains ubuntu
/dev/sda5: 3 gigs of swap
I'm having trouble with sda2 randomly being hidden, but I don't know what by. Recently when I've booted into windows, it just doesn't show up (usually drive D). When I go into ubuntu, it'll find it and mount it (at /media/Audio) just as usual, even if the hidden flag is set. I've repeatedly gone into GParted and unset the hidden flag, only for it to be reset when I reboot into windows. Even commenting out the entry for /dev/sda2 in /etc/fstab didn't fix it. Does anyone have a clue what might be causing this? I'd really like to have my music back in Windows.

Ah, using the WifeKillerFS, eh?

That I am, or allegedly so.

Make sure it is set up in windows to be used. Go to the control panel->Administrative tools (or something like that), in one of those (i think computer management), there will be a listing of all the partitions windows sees on your computer. Just find the 10gb one and tell it to use it as drive D: - that *should* fix your problem, unless there is something else wrong

I've tried that, but it won't let me have the partition mounted, presumably because it's getting marked as hidden somewhere along the way.

could something in GRUB be doing that at all?

I'm actually using LILO, but I don't think so... I got it to work once, but now it won't. I think windows might not like something ubuntu did when it wrote to the partition, so I'm going to copy all the data off it, and recreate the partition. Hopefully it'll work.

It sounds fairly clear to me from the evidence that Windows is hiding the partition somewhere in its boot sequence, but I couldn't help you with a solution.

...why?

did you ever think of just doing a fsck on it?

In a discussion on the bug with the kernel messing up JMicron, someone mentioned that GRUB was throwing errors in the boot sequence, too, so I just installed LILO to be safe.
I reformatted the partition and copied everything back, so I'm rebooting to see if it's fixed now.

GRUB has far surpassed LILO, you might want to consider switching, just to see if that is causing the problem or not

I'll see about that.
I got my problem fixed. Seems like Windows didn't like whatever Ubuntu had done to the partition. After reformatting in linux, windows didn't like it, but then I reformatted the partition in windows and copied everything back onto it, and everything worked fine, even after booting Ubuntu then going back. I think it was just something crazy going on with Ubuntu writing to it and vista doing non-standard things to the file system, so I'm now always mounting that as read only.

*bump* I've figured it out! When fsck runs at startup for Ubuntu, it finds crazy stuff that Vista is doing to the partition (no, you don't want to know), it "fixes" all that, which Vista sees when it boots and sez "Filesystem error!" and hides the partition. I guess formatting the partition as ntfs should fix it... or as ext2 or something and figure out a way to let windows read it. Or, does anyone know how I can stop fsck from scanning sda2 at boot time?

Ah, you figured it out! Good for you. Unfortunately, I can't truthfully say I know how to remove that, but I'd say /etc/init.d might be a start...

Yes, we do.

You could use NTFS, since you're only reading from it anyways...(yes, there is in fact write support for ntfs in linux, but I wouldn't use it comfortably just yet)

Well, from what I could tell, windows was throwing album art and such into the filesystem, but it was hiding it (precede the name with a $) and doing crazy things.
And I actually did reformat the partition as NTFS.