VPS expands to Virtual Private Server. It is also referred to as the Virtual Dedicated Server or VDS. This is basically a method of dividing a physical server computer into many servers in such a way that each of the individual servers has all the capabilities and appearance of running its own machine. Each of these virtual servers can have their own operating system in a full fledged manner and they can also be rebooted independently.

This practice of dividing a single server in order to make it look like multiple servers has been a common practice for long in main frame computers. But lately this has seen resurgence, due to the development of virtualization software and technologies for other architectures. Here the physical server always boots normally. Then it runs a program that boots each server with a virtualization environment. The virtual servers have no direct access to the hardware system and are generally booted from the disk image. You can always have the advantage of having more control over your hosting environment while using the vps server. It is also known widely that the shared hosting accounts are not always as safe as the vps hosting accounts. For instance if a hacker tried to find access to a shared server he can always damage all of the websites that are on the server in just one blow.

But since a Virtual Private Server is partitioned into many accounts that are isolated, even if a hacker manages to gain entry into any account he will not be able to access the others. The virtualizations are divided into two kinds one is the software based virtualizations and the other is the hardware based virtualization. In the software based virtualization environment the virtual machines always share the same kernel. They also require the main node's resources. Software based virtualization normally has its benefits in a web hosting environment due to the quota incrementing and decrementing in real time with no need to restart node. For example we have the Virtuozzo which is a product of swsoft.com, and there is the HyperVM which is a product of lxlabs.com. Then there is Vserver and the OpenVZ which is a core kernel of both virtuozzo and hypervm.

Then comes the second category of the virtualizations which is the hardware based virtualization. In this kind of virtualization, its mechanism divides the real hardware resources. Here no burst or real-time quta modification is possible. Here the limits are hard and can be modified only by restarting the virtual machine. Generally this kind of environment is considered potentially more secure since it is not really subjected to the quality of service cross talk between VM instances. But on the other hand, its security if to a large extent dependent on the correctness of a more complex trusted computing base. This is very commonly used in commercial or enterprise deployments.

Examples of the hardware based virtualizations are Microsoft Virtual Server, Vmware esx Server and Xen. The VPS or the virtual private servers have many uses. They are used to bridge gap between dedicated hosting services and shared web hosting services. This gives an independence from the other customers of the Virtual private server service in terms or software and also at a lesser cost than the physical dedicated server.