Microsoft has posted download information for the Release Candidate of Virtual Server 2005, Enterprise Edition. You can get this version with a license that expires Jan. 1, 2005, simply by registering at the Microsoft link below.\u00a0 Try it out (in the lab, please, not on a production network).Virtual Server 2005, which confusingly, is intended to run on top of Windows Server 2003 as its "host" operating system, is the logical follow-on to Microsoft's Virtual PC 2004. Both Virtual Server 2005 and Virtual PC 2004 derive from the technology Redmond acquired when it purchased Connectix 18 months ago.While Virtual PC 2004 was designed to best support Microsoft's desktop operating systems (Windows XP, W2K, NT Workstation, 98, 95, ME, Windows 3.1, and OS\/2), Virtual Server 2005 is optimized for NT 4, Windows 2000 Server and Windows Server 2003. That's right, you can install Virtual Server 2005 on its designated Windows Server 2003 platform and then configure it to run multiple instances of Windows Server 2003!Virtual Server 2005 (let's call it VS2K5, for now) is, supposedly, optimized to virtualize Microsoft server operating systems but it will also support non-Microsoft products such as Linux, NetWare or any other x86 based operating system.The Enterprise Edition will support up to 32 physical processors (no Itaniums, though) partitioned in up to 64 operating systems instances, limited only by the resources each instance needs - typically, RAM is the limiting factor. Once VS2K5 is released, there will also be a standard edition supporting up to four physical processors. You can assign one operating system instance per processor, but you can also have multiple operating systems using one processor, or multiple processors running one operating system, provided, of course, that the operating system you've virtualized supports multiple processors.Exploring the licensing requirements and implications for all of these virtualized machines, as well as VS2K5 itself and its underlying platform, is not a trivial task and should be sorted out and verified before you go to production. Still, the benefits of virtual systems (see https:\/\/www.nwfusion.com\/newsletters\/nt\/2003\/1117nt1.html for my thoughts on that) outweigh the hassle of getting properly licensed, in my opinion.Microsoft has outlined a number of scenarios in which you'd appreciate the benefits of virtualized machines, including:* Legacy application migration - legacy operating systems and applications can run on new hardware along with more recent operating systems and applications.* Server consolidation - If several servers run applications that consume only a fraction of the available resources, virtual machine (VM) technology can be used to enable them to run side by side on a single server, even if they require different versions of the operating system or middleware.* Isolation for development, testing and technical support - each VM acts as a separate environment, which reduces risk and enables developers to quickly recreate different operating system configurations or compare versions of applications designed for different operating systems. In addition, a developer can test an early version of an application in a VM without fear of destabilizing the system for other users.* Software demonstrations - VM technology allows users to recreate a clean operating system environment or system configuration quickly.* Courseware delivery and training - organizations can configure and deploy a variety of training scenarios quickly.Try it out and see for yourself.