Microsoft Virtualization Secrets

Embracing Retro Virtualization: Why an Old Form of Virtualization Is Still One of the Best

Figure 7-1: High-level view of sessions in the Windows operating system

Many people mistakenly assume that virtual desktop infrastructure (VDI), which virtualizes a client operating system and makes it available remotely, is a replacement for session virtualization. In fact, both VDI and session virtualization are viable technologies; in some scenarios one makes more sense than the other, and for most organizations both VDI and session virtualization will be used. Session virtualization is by far the more economical of the two technologies. Compared to VDI, it serves more users for each dollar spent while offering the same user experience for most use cases.

Prior to Windows Server 2008, users logging on to the console of a system used session 0, which was the same session used for system services. Windows 2008 reserves session 0 for key services, and user sessions use 1 and above.

As described in Chapter 1, various forms of session virtualization have been around for a very long time. I recall my early days of remotely connecting to a large server that hosted my session along with many other users, and my interaction was achieved through a dumb terminal that simply displayed text sent from the server and then sent back to the server keystrokes I typed in. My interaction with the session ...