Friday, 8 August 2008

Testing Virtual Machines

Recently I received a new laptop computer.  The new laptop is very nice with a wide-format screen, 2 gigabytes of RAM, and a big 160 gigabyte hard drive.  And since my old laptop was still doing fine I decided it was time to experiment with Virtual Machine (VM) software.  For those who might not have kept up on VM technology, simply said it is software that lets one emulate various computer operating systems such as Microsoft Vista or XP, Linux, UNIX, or even MS-DOS on a host computer.  In other words, one creates a “virtual” computer using software within a host system.  For a much more complete explanation of VM software see:

I’ve been testing Sun’s virtual machine software called VirtualBox.  But of course there are many other options to explore such as industry leader VMware as well as Microsoft’s Virtual PC 2007 software.  Apple Mac users have Parallels Desktop and VMware Fusion to choose from.  An excellent list of different VM software is posted on Wikipedia at:

I have posted a picture here to show you that I was able to load MSDOS, OpenSUSE Linux, and Vista on top of the installed Windows XP on my laptop.  Now to be realistic, I would need more RAM (chip) memory in my machine if I were to run all of these are the same time.  But it does seem to do the job quite nicely, and has the advantage of being free to use.  I thought you might enjoy the picture.

Now why are VM’s useful?  I can think of three reasons off the top of my head.  First, the obvious one is if there is a particular piece of software that only available on a particular operating system (OS), one can install that OS (legally licensed of course just like my Vista software) and then install the application.

Second, the ability to run older software programs to retrieve data could be particularly useful.  One might notice in the picture, my old CMS from the 80’s in Arizona is running in the MS-DOS window.  Therefore, if I had a court’s data from that system, I could run search and run reports without needing to convert the data.  It is interesting to note that there is as project is building VMs for older minicomputer systems of the past:

A third reason is to be able to test software on different applications in “clean” OS environments.  One can also emulate client / server networks or browser / server networks within a single machine.  Many VM’s have the ability to create “snapshots” of a system that allows a baseline configuration from which new software or configurations can be tested.  And if the approach doesn’t work; no problem, delete it and try again.  In the near future I am going to build a Linux client working with a Microsoft server to learn the best way to configure such a system.

Using VM?  Let us know and we’ll post your story.

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