Virtualization Software

Virtualization software are programs enabling you to run multiple operating systems simultaneously on a single computer. Using this software is fairly easy. After launching the virtualization program you install a "guest" operating system that will be known as a virtual machine in contrast to the main operating system called the "host." After installation, the virtual machines seem to be real computers. Many users will not even know that they are virtual. What are the benefits of virtualization?

The system can become easier to manage, for example by reducing backup and recovery time in part because a virtual machine is composed of very few files, instead of thousands of files. Testing software configurations on virtual machines is quicker and less dangerous than testing them on the host computer. Hardware upgrades can be done via a console server, thereby reducing the time needed to deploy them. You can maintain legacy applications without interfering with the rest of the system. You can support several platforms such as Windows, Linux, and Macintosh. An individual computer can be “split in two” allowing an individual to learn real-life networking configuration without having to purchase two computers. Virtualization may save energy and space by running fewer computers.

Of course there are disadvantages as well. This software is not always free (more about that later.) Under certain circumstances performance will be affected. And some one will have to monitor and debug the virtualization software. I remember a situation in which networking became impossible because of a bug in the virtual network addresses. The solution involved modifying a system control table. It wasn’t enough to be a networking specialist to solve the problem; you had to access the virtualization software bug reports and implement the corrections.

VMWare is the major virtualization company.

VMWare is the major vendor of virtualization software. They offer a full range of products from the freely downloadable VMWare Player to workstation and server versions. VMWare products run on both Windows and Unix/Linux operating systems, as well as on the Mac. VMware's enterprise software, VMware ESX Server, runs directly on the server hardware and does not require an underlying operating system.

Microsoft also produces virtualization software.

Microsoft’s Virtual PC and Virtual Server are available for free downloads. Please note, even if the downloaded software is free don’t expect that server virtualization will be costless. There is some support for selected Linux systems running under the Virtual Server. Virtual PC for Mac enables users to run a Windows operating system and Windows applications on a Macintosh.

Parallels sells Desktop for Mac, the first commercial virtualization product running under Mac OS, a similar server program, and products that run on Windows and Linux hosts. If you are seriously thinking about virtualization you should consider these products even though they aren’t free.