How to Limit the Amount of Memory Available to OS

Linux:

set the mem=2000m as the boot arguments, then the Linux only use first 2000MB memory. If the total RAM is 2G, it reserves 48MB.
http://fengweizhang.blogspot.com/2012/06/boot-arguments-on-linux.html


Windows:

Add line
MaxPhyPage=0x7D000 
at [386enh] section of C:\WINDOWS\system.ini
0x7D000 * 4KB = 2000MB
http://support.microsoft.com/kb/181862