I am using debian distribution on many machines. I have observed a strange thing regarding linux memory manager, top program or a strange bug.
I have compared top output on two machines. On of them is a realy old junk (P 188, 16 ram MB, HDD 512 MB) and the other is my laptop (P II 300, 128 ram MB, HDD 18 GB).
On the first one, top reports something about 12 MB of ram, on the other 128 MB of ram.
The only diference about both instalation is XFree, KDE and XDM installed on the laptop (which starts at boot time).
The thing is, the old PC report 280 kb of physical mem free, and on the laptop there is 3000 - 4000 kb free. This does not change when I start other programs. The usage of swap and free memory changes a little but not much (100 to 400 kb).
I removed apache, mysql, samba, exim, postgresql and xfs-xtt from startap, I rebooted my laptop and the usage of memory stayed the same! Why ? When at run time I did stop xfs-xtt, I got an extra 25 MB of free mem in top! Why does this happen ?