about changing to ext3 or anything else
 

is this step is to be made after finishing the installltion of lfs compeletly or when?

i want to make it work on ext3 for an example

You need to format a partition as ext3 before you start using it. So it would have been done in chapter 3.

However, if you currently have an ext2 partition you can convert it to ext3 at any point you want.

Have a look at the following page from the Beyond LFS book, it'll explain how to do it:

http://beyond.linuxfromscratch.org/v...tlfs/ext3.html

ok so i will go on installing lfs 4 on ext2 and after i finish it i will change it to ext3

thanx for help