Thanks for the interesting link. Just one minor nitpick (I can't help myself )

Well, kind of. du is supposed to report the disk allocation associated with the file. On an ext3 filesystem where the block size is 4k, even a 1 byte file will have a 4k block allocated to it, and du will show this.

On a compressed filesystem, this might be misleading because the "4k block" has only a virtual existence and doesn't reflect the actual disk usage associated with the file. At least as I understand it.

You can see this below. ls shows the file size (1 byte) whereas du shows (what it thinks is) the disk allocation..

~# echo > testfile
~# ls -l testfile
-rw-r--r-- 1 root root 1 Dec 22 12:18 testfile
~# du -h testfile
4.0k testfile