I am beginner on Linux. I installed CentOS with virtualbox. At the time to create this VM, I assigned 2G(2048M) memory for this VM. My host PC has 8G memory. After installed CentOS, I start it, then I check the memory with ''free -m", the out put for Total Mem is 1877. It is not 2048. Anything wrong? how to find out the physical memory of the machine to host Linux?