The environment in which a hosted operating system runs on top of a hypervisor, providing the abstraction of a dedicated machine. By employing virtualization software, “space” is created within the host operating system allowing the user to install another guest operating system utilizing Windows, Linux, etc; which acts independently from all other virtual machines on that host.

A virtualization platform that allows multiple operating environments to run on a host computer at the same time. The term hypervisor, as depicted here, is said to have been coined by IBM back when they first introduced the virtualization concept.

The process of detecting a device or system failure and taking appropriate action. Actions could include a fail-out process, in which the fault is masked from the operating environment and end-users, or failover in which a restart is immediately and automatically initiated. An appropriately implemented fault management process should help to eliminate interruptions during failures to provide a measure of fault tolerance.

When two servers (CPU, Memory, I/O) are joined and initialized to the same state during system start-up. Once joined, the two servers execute the same instructions and act identically; and are said to be lock-stepped. From the outside, the two systems look and behave like a single server. But the redundant hardware and execution environment provide all the needed resources to transparently handle a server or component failure.

Software technology that makes it possible for multiple systems to be provisioned and managed as if they were a single computing resource. (See the original article by Dan Kusnetzky here)

Hardware and software technology that presents a view of the network that differs from the physical view. So, a personal computer may be allowed to only see systems it is allowed to access. Another common use is making multiple network links appear to be a single link. (See the original article by Dan Kusnetzky here)

Hardware and software technology that hides where storage systems are and what type of device is actually storing applications and data. This technology also makes it possible for many systems to share the same storage devices without knowing that others are also accessing them. This technology also makes it possible to take a snapshot of a live system so that it can be backed up without hindering online or transactional applications. (See the original article by Dan Kusnetzky here)

Hardware and software technology that hides physical hardware configuration from system services, operating systems or applications. This type of Virtualization technology can make one system appear to be many or many systems appear to be a single computing resource to achieve goals ranging from raw performance, high levels of scalability, reliability/availability, agility or consolidation of multiple environments onto a single system. (See the original article by Dan Kusnetzky here)

Software technology allowing applications to run on many different operating systems and hardware platforms. This usually means that the application has been written to use an application framework. It also means that applications running on the same system that do not use this framework do not get the benefits of application virtualization. More advanced forms of this technology offer the ability to restart an application in case of a failure, start another instance of an application if the application is not meeting service level objectives, or provide workload balancing among multiple instances of an application to archive high levels of scalability. Some really sophisticated approaches to application virtualization can do this magical feat without requiring that the application be re-architected or rewritten using some special application framework. (See the original article by Dan Kusnetzky here)

Hardware and software technology that allows nearly any device to access any application without either having to know too much about the other. The application sees a device it’s used to working with. The device sees an application it knows how to display. In some cases, special purpose hardware is used on each side of the network connection to increase performance, allow many users to share a single client system or allow a single individual to see multiple displays. (See the original article by Dan Kusnetzky here)