In computing, virtualization is a broad term that refers to the abstraction of computer resources. One useful definition, from independent IT analyst firm Enterprise Management Associates, is "a technique for hiding the physical characteristics of computing resources from the way in which other systems, applications, or end users interact with those resources. This includes making a single physical resource (such as a server, an operating system, an application, or storage device) appear to function as multiple logical resources; or it can include making multiple physical resources (such as storage devices or servers) appear as a single logical resource."
However, the term is an old one: It has been widely used since the 1960s or earlier, and has been applied to many different aspects and scopes of computing – from entire computer systems to individual capabilities or components. The common theme of all virtualization technologies is the hiding of technical detail, through encapsulation. Virtualization creates an external interface that hides an underlying implementation, e.g. by multiplexing access, by combining resources at different physical locations, or by simplifying a control system. Recent development of new virtualization platforms and technologies has refocused attention on this concept.
Like such terms as abstraction and object orientation, virtualization is used in many different contexts. The common uses of the term are divided into two main categories:
- Platform virtualization involves the simulation of virtual machines.
- Resource virtualization involves the simulation of combined, fragmented, or simplified resources.
Of course, virtualization is also an important concept in non-computer contexts. Many control systems implement a virtualized interface to a complex device.
Date: 2014-12-28; view: 399