I read somewhere and understand that a fresh installation of Ubuntu 9.10 is using Ext4 file system by default for better performance, but by means of upgrading from 9.04, it will use back the Ext3 file system which I think is not the best choice.
On my PC, the Ext file system cannot be read by Windows, but since 2007 Linux can
read and write NTFS developed by M$.
I can read yours, you cannot read mine, who is better?