Agile Aspect wrote: > I'm new to Xen and I'm not familiar with the jargon. > Xen is a full hypervisor that boots in FIRST, then loads a supervisory master OS into "dom0", typically this is CentOS5 (or another late model linux distribution) which Xen is bundled with.... Then you can load other guest OS's into dom1, dom2, etc which are collectively known as domU (eg, U = 1,2,3...). VirtualBox is a guest hypervisor that runs under a parent OS. If you couldn't get Virtualbox working, you might try VMware Server, I've had very good luck running this on CentOS 4, and hosting both linux and windows domains under it. Note there are some constraints with all these virtualization systems... To run a 64 bit guest OS you need a processor that supports hardware virtualization assist, AMD-V or Intel VT. Early Opteron and Xeon 64bit CPUs didn't support this, later ones do.