Understanding Virtualization

Virtualization is an approach to deploying computing resources that isolates different layers--hardware, software, data, networks, storage--from each other. Typically today, an operating system is installed directly onto a computer's hardware. Applications are installed directly onto the operating system. The interface is presented through a display connected directly to the local machine. Altering one layer often affects the others, making changes difficult to implement.

By using software to isolate these layers from each other, virtualization makes it easier to implement changes. The result is simplified management, more efficient use of IT resources, and the flexibility to provide the right computing resources, when and where they are needed.

There are different types of virtualization. Machine virtualization uses software to create a virtual machine that emulates the services and capabilities of the underlying hardware. This makes it possible to run more than one operating system on a single machine. On servers, this approach is called server virtualization; on end-user PCs, it is called desktop virtualization.

Application virtualization separates the application from the operating system, reducing conflicts between applications, which can simplify deployments and upgrades. Presentation virtualization enables an application on a computer in one location to be controlled by a computer in another.

There is also storage virtualization, which lets users access applications and data without having to worry about where they are stored. And network virtualization allows remote users to tap into a company network as if they were physically connected.

Virtualization is not new. IBM first introduced virtual machine technology for mainframe computers in the early 1960s. Microsoft Windows NT included a virtual DOS machine. Virtual PC was introduced by Connectix in 1997 (Microsoft acquired Connectix in 2003). EMC's VMware introduced its first product, VMware Workstation, in 1999. Softricity introduced SoftGrid, the first application virtualization product, in 2001 (Microsoft acquired Softricity in 2006).

Currently, industry analysts estimate that fewer than 10 percent of servers are virtualized, despite the fact that virtualization has been around for many years. But its significance is growing as companies have introduced products that target today's high-volume, low-cost hardware. Now, more and more companies are using server virtualization to save money by consolidating the workload of several servers onto a single machine.

Virtualization: A Foundation for Dynamic IT

As important as server virtualization can be in reducing costs, saving money is just the beginning of the value that virtualization offers. At Microsoft, we believe that virtualization will play a significant role in enabling companies to create IT systems that are not only highly efficient, but that have the self-awareness to adapt automatically as business conditions change.

By separating the layers of the computing stack, a virtualized IT environment makes it possible to quickly deploy new capabilities without having to configure components. In a virtualized environment, testing requirements and application compatibility issues are reduced, processes are easier to automate, and disaster recovery is easier to implement.

In the data center, virtualization not only supports server consolidation, but it enables workloads to be added and moved automatically to precisely match real-time computing needs as demand changes. This provides greater agility, better business continuity, and more efficient use of resources.

On the desktop, application virtualization reduces management costs. And when the operating system, applications, data, and user preferences are all virtualized, it makes it possible for users to access the computing resources they need anywhere, from any machine. The result is tremendous flexibility for employees and greater efficiency and agility for IT departments.