sharing /home between FC4 and Ubuntu

I am dual booting with Fedora Core 4 and Ubuntu. I'm trying to share /boot, /home and swap between 2 OSs. My hard drive is partitoned something like this :
| /boot | / FC4 | /home | / Ubuntu | SWAP |

I'm sharing swap and /boot with no problems. I had some problems with sharing boot at first but some manual grub.conf editing took care of that and allowed me to boot to both OSs. Anyway, I had FC4 installed first so /home was obviously created with that install. When I first booted to Ubuntu, it came up to a graphical login, when I entered my login info I got some error messages that are related to permissions and it would take me right back to the graphical login prompt - I am able to log into a terminal session though. I've done some research and pieced together some useful information but nothing definitive for this problem. After checking out the Ubuntu forums
(http://ubuntuforums.org/showthread.php?t=87999) and a little tinkering with permissions from the Ubuntu side - namely setting permissions like this: (syntax may be wrong but you get the idea)
sudo chmod -R /home/<user>
sudo chown -R /home/<user>
then I was able to log into gnome under Ubuntu and everything seems to work OK.

When I booted back into FC4, I now had similar problems with files under /home/<user> - just as I expected. I found an old post on fedoraforum.org
(http://forums.fedoraforum.org/forum/...ad.php?t=29254 )that says to modify the /etc/passwd and /etc/group to fix the issue with mismatched UID/GID between the two OS's. which is what I sort of suspected the problem being but I don't know enough about doing this... can anyone provide some more details?

no takers eh?

I wanted to post my results thus far for any others interested.

In my research I found some websites and forum posts recommending not to even try this, and I found others making it sound like this is the recommended way to dual boot multiple linux flavors. Being the daring guy I am, well I tried it. All I had to do after installing both OS's (FC4 and Ubuntu sharing a /boot, /home and swap partitions) was to modify /etc/passwd and /etc/group on each / partition so that the UID and GID numbers matched for my user name. I did not modify any other lines in thes files, if anyone knows if any others need to be modified let me know. After doing that I had to modify pemissions on everything under my /home/<user> directory so they matched what was now in the group and passwd files. This was easy enough to do with (from Ubuntu)
cd /home/<user>
sudo chown -R <user> * then
sudo chown -R <user> .* to get all the hiden . files
I did have to tinker with permissions a little after changing this, apparently Ubuntu is more picky about what the permissions are set to than FC4. When I tried to log into Ubuntu it gave me some errors about permissions not being set correctly on some files in the /home directory - namely .dmrc and .gnome2_private. I set permissions to everything in my /home directory with
cd /home/<user>
sudo chmod -R 760 *
sudo chmod -R 760 .*
that allowed me to get logged into Ubuntu and Fedora just fine.

I've had a few odd problems but nothing major like I cannot launch firefox by clicking on a URL from an e-mail or external document from Fedora, not sure what that is about. I just get a message saying "there was an error launching the default action command associated with this location."

Just as a precaution, I'm using KDE on Fedora and Gnome on Ubuntu just to avoid problems there, I haven't even tried sharing those settings, it just seems like a bad idea but I may try it down the road.

MOST of the problems I've run into thus far have been permissions related due to the mismatchd UID/GIDs, but again, nothing major.

If I fiind more major issues I'll post them but for anyone with a decent amount of linux knowledge and some patience, this seems like a reasonably easy way to dual boot multiple versions of linux and retain some of your settings and such between the two.

I tried this between Mandrake 9.0 and Redhat 8. It was a complete disaster. When you fix it to work with one distro, it breaks it in the other... :wink:
I always create a new home for all distros on the same machine and just link from one to the other for easy access of files. :)

Stumbled across this old post of mine and wanted to update after having this set up for about 1 year. I've had very few problems that I can chalk up to sharing the /home partition with 2 distros. With that said, I hardly ever use Ubuntu, mostly just use Fedora so I suppose there could be problems with Ubuntu that I've never discovered. All in all, I probably wouldn't set it up like this again but if you're up for the challenge, it was kind of fun to see if I could figure out how to do it and make it work even after being advised not to do this time after time. I learned a lot about where to find config files and how linux works.