This week we will wrap up some of the technical delights of how VMware works and conclude with a higher-level look at where this product fits into IT operations.

On the technical side, one thing we haven't covered is what it takes to run VMware. Because all the virtual machines are sharing the same processor there's no such thing as too many cycles. VMware recommends you have at least a 500-MHz processor. We found that a 2.4-GHz Pentium 4 provided excellent performance.

There are a few processors not supported by VMware, including the Transmeta Crusoe, because they don't implement "certain processor instructions."

If you're going to run a bunch of guest operating systems you will need lots of memory. If your host operating system is Linux you will need at the very least 64M bytes (in reality 192M bytes is more practical) plus whatever the minimum requirements are for each guest operating system running simultaneously. We ran VMware with 2G bytes of RAM and we were comfortable. The maximum memory that VMware can allocate to an individual virtual machine is 1G byte.

Obviously, you will need a graphics adapter, and VMware recommends a 16-bit display adapter. But you can squeeze by with anything greater than an eight-bit adapter. An additional requirement for Linux hosts is an X server such as XFree86 that meets the X11R6 specification.

Basic installation requires disk space, and you will need 100M bytes for Windows hosts but only 20M bytes for Linux hosts. You also will need at least 1G byte of disk space for each guest operating system (the actual disk space needed will be roughly the same as the normal requirements for installing and running each guest operating system and its applications). See VMware's list of VMware Workstation requirements.

VMware also offers enterprise and data center-oriented products with GSX Server and ESX Server, which support partitioning and isolation of server resources with remote management and automatic provisioning.

Designed for large systems, VMware GSX Server runs on Windows 2003 Server, Web, Standard and Enterprise Editions; Windows 2000 Server, Advanced Server and Datacenter Server; and Windows NT Server 4.0. It supports up to 64G bytes of host memory, 32 host processors and 64 powered-on virtual machines, along with up to 14 virtual SCSI devices and shared cluster virtual disks up to 128G bytes in size.