VMWare was the first software of its kind to offer the ability for one operating system to host others in such a way that users could be interacting with multiple operating systems simultaneously. Each virtual machine shares the host computer's hardware resources such as CPU, memory, network connections, and hard disks.

Developers today often need access to several operating systems or configurations for testing. It is quite common to find developers using Microsoft Windows XP for their development, even though they know they'll be deploying ultimately to Microsoft Windows 2003 Server.

VMWare Workstation 5.0 supports a myriad of host operating systems, including the current lines of desktop and server operating systems, Windows XP and Windows 2003 Server, and several major editions of the Linux operating system, including Red Hat, SUSE, and Mandrake.

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VMWare Workstation 5.0 has even more extensive support for guest operating systems with some notable options such as the new Sun Java Desktop, Sun Solaris operating systems, and the forthcoming Microsoft Windows Vista Professional operating system, which is now available in its first beta.

The latest version of VMWare Workstation also provides support for 64-bit operating systems when used in conjunction with microprocessors that provide support for 64-bit computing. Currently the processors supported are AMD Opteron, Atherlon-64, and Intel EM-64-based processors.

In this release, VMWare has reduced the memory utilization of the virtual machines, although I would recommend having at least one gigabyte available because the guest operating system will likely require at least 512MB, and it can really benefit from more. The published minimum on their Web site is a mere 128MB, although I would venture to guess that this should be revised.

VMWare guest operating systems can communicate with the network by using various configurations, although the two tested were where the guest operating system either has its own dedicated IP address or shares the host operating systems.

To conduct this test the hardware used was a somewhat modest Intel Pentium 4 2GHz machine equipped with 1.5 GB of memory. The hard disks were 10,000rpm, which certainly helped the performance, although any 7,200rpm drive will be more than adequate. The author found it to be a good idea, however, to have the virtual hard drive be on a separate physical disk apart from the one that contained the host operating system.

In my day job as a .NET architect, VMWare Workstation 5.0 has proven to be invaluable with regard to the frequent builds of Visual Studio 2005 and SQL Server 2005. The tool provides an excellent option for testing beta-quality products without affecting other software installed on your machine, and with Microsoft expected to be discussing Visual Studio Orcas at PDC, my dependence upon VMWare is likely only to increase.