I have same problem as Renan.
Running 8.10x64 for some months without issue.
Upgraded to 9.04x64, and after a day or two the system became unusable
due to filesystem corruption.
Attempting to mount harddrive from live cd produces:
ubu...@ubuntu:~$ dmesg |tail
[ 187.346997] mount -t ufs -o
Same problem over here.
Running nVidia GeForce 9300 on an ASUS X83Vb.
Ubuntu 9.04 x64
I upgraded from 8.10 - 9.04 and the driver installed but my X server
kept crashing over over.
I installed 9.04 fresh and got the jockey backend crash described here.
I'm going back to 8.10.
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jockey