Updating Ubuntu from 9.04(Jaunty) to 10.04(Lucid) with clean install (not update)

Since Ubuntu 9.10(karmic) have some issue with my external hard disk.  I stopped and wait until 10.04 release.  Here is how I update from 9.04 to 10.04 using clean install.

1), change the /home from ext3 to ext4.

2), format the root(/) to fat32 (using GParted in the Ubuntu Desktop version).

3), format the root(/) to ext4 (using GParted in the Ubuntu Desktop version).

4), install Ubuntu 10.04.

5), when install, choose where the root is install, and also set your /home partition as /home. (It will not format the /home, just for mount issue when startup.)

Note that on the step 2 and 3, it seems that it could directly format to ext4, or when install 10.04, it will format directly.  But as I tested on other disk, It did not success, and it shows that it cannot remove another operating system (that is, 9.04).  So I format the root to fat32, and than format back.  Another reason is that if you delete the partition and create a new partition, the partitioning table on the harddrive may not work as what you expected.  It may change from sda5 to sda9 (in my case).