Virtualization is one of the hottest technology topics these days. Most people have probably heard about it in the context of Apple’s switch to Intel processors and the release of Parallels Desktop for Mac. Parallels allows you to run Windows applications on an Intel Mac by starting up a full copy of Windows within a window. You can run Windows in full-screen mode and even put Windows and OS X on separate screens if you have two displays. I’ve been waiting patiently (OK, not that patiently) for the Core 2 Duo upgrade before ordering a new MacBook Pro for work, and since there are a couple Windows apps I need to run I’ll be ordering a copy of Windows XP and Parallels to go with that new laptop.
It’s called virtualization because software like Parallels creates a “virtual machine” (VM) on top of which runs a “guest” operating system. Any guest OS that runs on PC-compatible hardware (e.g., Intel, AMD) can run in a Parallels VM. So my MacBook Pro will probably ended up running OS X, Windows, and Ubuntu Linux—maybe even simultaneously. I won’t go into any technical details because that’s been done many times.  
The king of virtualization in modern times is VMware. The VMware software was built originally for virtualization on the desktop, but the really interesting stuff has been happening on the server side. If you’ve installed any Windows server software lately you know that a lot of those programs don’t play nicely together. Many IT departments end up buying separate servers for each application, and the result is that those servers go underutilized from a processor and memory standpoint. That’s where virtualization comes in. The benefits are pretty clear when you look at a simple example:
Let’s say I’ve got four separate Windows application that would normally require separate servers. It’s hard to buy a “real” server these days for less than $5,000 so let’s use that as a baseline. By utilizing VMware I could buy a beefier server for $10,000 and install my Windows applications in separate VMs on that server. The newest, high-end version of VMware isn’t free, but even with a $2,000 VMware license I’m still way ahead.
(4 × $5,000) − ($10,000 + $2,000) = $8,000!
That’s way oversimplified (and probably overly optimistic), but it doesn’t take into account additional savings in rack space, cooling requirements, and electricity use.
That’s it for now. I’ll post soon about some free virtualization products.