How to reserve memory while system boot
 

Hi,
whether its possible to reserve memory in linux .Dmidecode should shows up the memory but free -m should not ..Does any one has any clues to do it

Depends on how you define "reserve memory". It is entirely possible to tell the kernel to not use all of physical memory... but that doesn't make it available for anything else either. The original purpose was to give the graphics cards access to main memory for its dedicated use.

The kernel boot option is "max_addr=nn[KMG] on ia64. All physical memory greater than this address is ignored.