Other virtualization technologies

There's also storage virtualization, application virtualization, and session virtualization.

Storage virtualization: abstraction of logical storage from physical storage. Storage Area Networks (SANs) are typically associated with virtualized storage, since they allow an administrator to consolidate disparate physical resources into a single location, then "carve up" those resources into logical units or LUNs.

Application virtualization is the abstraction of an application and all associated files from the OS. Thinstall, Microsoft Softricity and Altiris SVS are all application virtualization technologies. They capture the steps associated with an application install and the binaries that are provisioned during that install. Once captured, those steps, binaries, and settings can be redeployed to other systems as needed.

Session virtualization is the abstraction of the application's location from the user session. Citrix and Windows Terminal Services are examples of session virtualization technologies. They allow all of the processing and data storage resources to be consolidated in one place while UI elements are still presented to the user wherever and whenever needed. Session virtualization is subtly different from the distributed processing paradigm of mainframe days in that the client typically offers much more functionality than mainframe terminals, so it can balance the need for centralized vs. distributed UI and processing requirements.