Virtualization

In computing, virtualization involves the process of presenting computing resources in ways that users and applications can easily get value out of them, rather than presenting them in a way dictated by their implementation, geographic location, or physical packaging. In other words, it provides a logical rather than physical view of data, computing power, storage capacity, and other resources.

Virtualization can manifest itself in several ways:

• Virtual machines - running one or several operating systems, known as "guests", over an operating system actually running on the system, known as a "host", and (to varying degrees) emulating hardware by means of software.

(see Paravirtualization)

• Partitioning - Splitting a single, usually large, resource (such as a computer system, disk drive, or network switch) into a number of smaller, more easily utilized resources of the same type. (Sometimes also called "zoning".)
• Aggregation, spanning, or concatenation - Combining multiple resources into a smaller number of apparently large resources. For example, symmetric multiprocessing combines many processors; disk concatenation combines many disks into one large logical disk, and some network equipment uses multiple links combined to work as though they offered a single, higher-bandwidth link. At a meta-level, computer clusters do all of this.

Virtualization software

• VMware
• Xen
• Virtual PC

See also

• Virtualization Technology
• Hypervisor
• Emulation
• Paravirtualization
• Comparison of virtual machines
• X86 virtualization

External links

• An introduction to Virtualization