question about dired-mode

[address@hidden]

Hi all emacs users,
I like emacs dired-mode very much, but one thing still annoys me. A
dired-mode buffer looks like this:

/cis/home/zma/research:
total used in directory 104K available 9378071488
drwxr-xr-x  2 zma zma 4.0K Aug 11 02:33 BIRN

I have put this in my .emacs to make file size more readable

(setq dired-listing-switches "-lAh")

However, the above line does not affect the total free space,
9378071488, ie the last number of second line. I will very appreciate
if somebody can tell me how to make this number readable.

Another question, what the two numbers in the second line, 104K and
9378071488, really means?

Thanks,
zma