Virtual PCs

by Bob Seidel

* Before we get into this week's topics, a note on the Time Warner cable box software update topic I started last week. I think that a very important function has been deleted, one that many people were actually not even aware of. If you have a DVR (Digital Video Recorder) box, it is always recording and you can rewind or fast forward within a program. With the old software, after you pressed the rewind or fast forward key once, you could then use the "left" or "right" key to skip in intervals of 15 minutes. This made skipping quickly to a different section of the recorded program easy. I believe this function has changed, and the left or right keys now take you to the previous or next entry in the Guide. Not the same thing.

* You may come across the term "virtualization" in relation to your PC. This is a complex topic and probably one you aren't going to have to worry about in normal life here at the beach yet. But some of you may have a need to know about it, so here is a brief explanation. What is interesting about this topic is that an increasing number of traditional mainframe implementations from thirty years ago are working their way into the PC world - especially as PC processor hardware becomes more capable. Virtualization is one of those functions. I worked on virtual systems at IBM in the '70s and they were very popular as they opened up a lot of new functionality.

The concept of virtualization is that through the use of special software, one or more entities called "Virtual Machines (VMs)" can be created on your PC. Each of these VMs is in effect its own, separate PC and you can boot up and run each of these virtual PCs independently of one another. As an example, you can have Windows Vista, Windows XP, and Linux virtual PCs running simultaneously side-by-side in a single real PC without interfering with each other. Hardware resources in your PC are shared between the VMs; for example, each VM might use its own hard drive partition, and the screen and keyboard can be switched between VMs whenever you wish to "talk" to a particular VM.

This is very different from a "dual-boot" system in which you can select which OS to boot up in your PC, but once you make that selection that is the only OS running until you re-boot.

Why would you want virtualization? Primarily it is used either to separate new applications under test from old ones, or to share hardware resources more efficiently. Let's say you are using a video editing package and a new version comes out that you don't trust yet. You could create two VMs, one to run your existing tested application, and the other to run the new version while testing it. You can thus install and test the newer version without disturbing the old installation.

In the case of large server farms (how Google is implemented) some servers may be doing different applications than other servers. But often you will find that the servers are idle a significant period of time. By putting both applications in VMs on a single PC, the PC is much better utilized. I have seen presentations that claim that on average ten current server applications could be combined into one physical PC with no performance issues.

In order to implement a VM system, you need specialized software. This software is what is actually booted up in the PC, and then it allocates and controls the virtual PCs. One of the most popular of these packages is VMware, now owned by one of the leading storage companies, EMC. Many industry pundits believe that Microsoft missed the boat again in Virtualization and is rapidly scrambling to catch up with other vendors in this area.

Virtualization software for the masses is not available yet, but stay tuned - especially if Microsoft determines that it is a key technology.

(Bob Seidel is a local computer consultant in the Southport - Oak Island area. You can visit his Website at or e-mail questions or column ideas to him at For specific inquiries, please call Bob Seidel Consulting, LLC at 278-1007.)