In the broadest sense, virtualization is the process of creating a virtual rather than an actual copy of something. Virtual in this case means something so similar to the original that it can hardly be distinguished from it, as in the phrase "substantially the same".
ContentsHardware virtualizationDesktop virtualizationNetwork virtualizationConclusionVirtualization is the use of computer programs to closely mimic a specific set of settings. A specific software tool, called a "hypervisor", creates a virtual environment with software within the given parameters.
There are as many types of virtualization as there are uses, so we'll limit our discussion to the most common types of virtualization.
This is the most common type of virtualization for most users. When you run a virtual machine in VirtualBox, you are running hardware virtualization. Video game system emulators follow the same principle, using a hypervisor to generate settings for older video game consoles.
In hardware virtualization, the hypervisor creates a guest machine, mimicking hardware peripherals such as a monitor, hard drive, and processor. In some cases, the hypervisor simply goes through the configuration of the host machine. In other cases, an entirely separate and independent system is virtualization, depending on the needs of the environment.
However, the whole system is actually managed by a server. This allows system administrators to have full control over users' desktop environment from a remote access point. By deploying updates on the server, they are instantly applied to the end user, without the need for tunnels, physical access, or device-specific user profiles. By separating the desktop environment from the hardware it runs on, the user is free to access “their” computer from any desktop.
Similar to the two types of virtualization already mentioned, network virtualization mimics network topology, but decoupled from the hardware traditionally used to manage such networks. Rather than running a physical network control infrastructure, a hypervisor recreates this functionality in a software environment. Network virtualization can be combined with hardware virtualization, creating a software network of hypervisors all communicating with each other. Network virtualization can be used to test and implement higher-level networking features such as load balancing and firewalling, as well as Tier 2 and 3 roles such as routing and switching. /P>
The main virtualization penalty is speed. Virtual environments are universally slower than host environments running on "real" platforms. But speed isn't all that matters. In environments where up-to-the-second performance is not critical, businesses can save money and increase flexibility with virtualization. Individual users can use virtualization to mimic hardware environments they don't have access to, running multiple operating systems simultaneously on a single computer.
