I don't know how OS X handles its virtual memory. Windows XP uses C:/PAGEFILE.SYS for the virtual memory and C:/HIBERFIL.SYS for sleep mode. Linux and AmigaOS 4.1 need a SWAP partition for this. But in OS X I don't find similar things.

I did a bit research but what I found wasn't really informative. But I read that some programs are reserving a specified amount of RAM (virtual and real) although they aren't using it completely. For example, if you run Parallels in which the virtual machine is set to 1 GB RAM Parallels must allocate 1 GB minimum, even if the virtual machine doesn't need it.

Same question like Ali C. i had 30 G on my boot partition and the system says in "Activity Monitor" VM Size: 53.47 G. So how does it fit?