Living in a Virtual World — It Has Real Benefits When Is a PC Not Really a PC? Joseph Moran
While the virtualization buzz is loud in big business circles, the technology also provides safer, more convenient networking for home offices and small businesses.
Question: When is a PC not really a PC? Answer: When it's a virtual PC.
Virtualization technology [define] lets you run one or more "virtual" systems on a single physical PC. Virtualization essentially works by borrowing a portion of your computer's resources — a percentage of the CPU, a bit of RAM, a chunk of hard disk space — and using them to emulate a "real" system. (Some system components that can't be explicitly shared — like the graphics subsystem, for example — are themselves emulated [define].) You can use virtual machines to run "guest" operating systems, which operate independently atop your "host" OS, just as if they were stand-alone computers.
It's easy to see the appeal of virtual machines. Although they're not intended for performance-oriented applications (especially graphics-intensive ones), they still have many practical uses. Do you have an old piece of software that runs best on a previous version of Windows? Run it in a virtual machine. Ditto if you want kick the tires on a new operating system —say, Vista or the newest version of Linux — or application you just downloaded from an unknown vendor, without the risk of messing up your system. You can even run server-based operating systems in virtual machines, allowing you to save money and space by consolidating multiple servers onto a single physical box.
Virtual Networking
The usefulness of virtual machines particularly stands out when it comes to networking. For example, a collection of virtual machines can be enormously helpful if you need to evaluate network software. A colleague of mine recently used this method to test an application designed to provide group calendaring in Microsoft Outlook without an Exchange server, which was a lot easier and safer than putting it through its paces on the company's production network.
Even a solitary virtual machine is useful, though, because you can make it as connected or isolated from your network as you want. As in the example above, virtual machines are often set up to be on an independent network, but they can also be configured to use local network resources such as shared folders or printers and have full access to the Internet.
This makes a virtual machine a great way to browse the Web without having to worry about the nasty stuff that might lurk behind every page — after all, better to accidentally infect a virtual computer than your physical one. And, since entire virtual machines are stored on just a couple of files, they're easy to backup and reuse should they become damaged. (Sure, you can use firewall or anti-spyware utilities — and you should — but they're not foolproof.)
Products to Take You Virtual
There are several virtual machine utilities available — their capabilities vary, but most provide the same basic set of features. Microsoft's Virtual PC 2004 — once a $129 product — is now available as a free download. As you might guess from the name, Virtual PC 2004 is a bit long in the tooth — it's more than three years old, its Linux support is fairly limited, and it won't run Vista, but it's hard to argue with free.
A new version — predictably called Virtual PC 2007 — is due to be released early this year and will be able to run (and run under) Vista. Best of all, it will still be free. (Note that although Microsoft states that Virtual PC 2004 isn't compatible with XP Home Edition — and will display a warning when you begin installing it on XP Home — it will install and work just fine.)
Another good virtual machine application is Parallels Workstation 2.2. It will set you back $49.99, but it features broader Linux support and can also take advantage of the virtualization extensions found in the newest processors such as the Intel Core 2 Duo and Socket AM2-based AMD chips. (These extensions improve performance by allowing some virtualization functions to be run in hardware rather than software.)
VMWare was an early pioneer in virtualization technology, and its $189 VMWare Workstation 5.5 is popular among corporations for enterprise-level features and support. VMWare also offers a free Player version that can run existing virtual machines but doesn't allow you to create new ones. To create virtual environments, you can also download for free the company's VMware Server product, which lets you partition Windows and Linux servers into virtual machines [define].
Getting Real Performance from Virtual PCs
As with any application, the more powerful the underlying system, the better your virtual machines will perform. A reasonably fast CPU will certainly keep your virtual systems humming, but the most critical component is RAM. You can adjust the amount of RAM a virtual machine uses, but any memory allocated to a virtual machine isn't available to the host system while that machine is running. To avoid bogging down your system, you should have at least 1 GB system memory, and if you plan to run multiple virtual machines, 2 GB or more is preferable.
Licensing Fees Remain Real
Unfortunately, there's a bit of a catch to the benefits of virtualization, and it involves software licensing. As far Microsoft (or most other operating system vendors) are concerned, installing an OS onto a virtual machine is considered the same as putting it on an actual system. This means that every virtual machine you run must have its own OS license, which precludes you from re-using the copy of Windows that came with your PC.
While you could certainly try to install the same copy of Windows multiple times, doing so isn't legal, and in any event would likely cause activation problems. Therefore, to keep things kosher, you should make sure than any copies of Windows you use aren't already running on another system. The need to purchase extra OS licenses certainly adds to the cost of running virtual machines, but it's still cheaper — and takes up a lot less space — than using dedicated hardware.
Joe Moran is a regular contributor to PracticallyNetworked.
