Virtualization Technologies

Virtualization software fills the need to run any application binary on any hardware/OS combination. There are many different ways to achieve this including full virtualization, para-virtualization and co-operative interpretation.

Products like VMWare and Microsoft's Virtual PC provide full virtualization of the hardware and require installing a complete operating system running on top of the virtualization layer (Virtual Machine Monitor (VMM) or the hypervisor).

Xen is an open source (GPL) hypervisor that provides para-virtualization. In para-virtualization, the guest OS is ported to an idealized hardware layer, which completely virtualizes all hardware interfaces. Read more about Xen here. Numerous companies have recently voiced Xen support such as Sun Microsystems, Hewlett-Packard, Novell, Red Hat, Intel, Advanced Micro Devices, Voltaire and interestingly IBM which has it's own multi-platform, multi-purpose hypervisor called rHype.

coLinux (or Cooperative Linux) is a free and open source software (FOSS) that provides a method to run Linux on Microsoft Windows natively. It's a port of the Linux kernel that allows it to run cooperatively alongside another operating system on a single machine. Check out the getting started guide if this gets you excited.

Apple is bundling Rosetta with it's new Intel-Macs based on technology by Transitive. This allows users to be able to run applications targeting the PowerPC processors on Intel-Macs.

Microsoft has also recently released information about their upcoming hypervisor that will be built directly into Windows. It will be delivered in 2007, following the debut of Longhorn Server (possibly as a service pack) and will take advantage of upcoming virtualization technology built into processors from AMD and Intel. More on this here.