Every single notebook or desktop or web server is run by an Operating System - the low-level program which interacts with the computer hardware, including peripheral devices such as a mouse and a printer, together with any apps that are present on your system. Any program input using a command line or a Graphical User Interface (GUI) is processed by sending an Application Program Interface (API) request to the Operating System. On a server, every single application runs within the parameters set by the OS as well - priority, physical memory, processing time, etcetera. This goes for both standard site scripts and server-side software like a media server. When a virtual server is created on a physical one, there can be two independent Operating Systems, referred to as guest OS and host OS, so you can set up a different software environment on the same machine.
Multiple OS in Dedicated Servers
If you decide to get one of our dedicated servers, you'll find three Operating Systems on the order page since we want to give you a wider choice for the system environment on your machine as different apps may have particular requirements. CentOS, Ubuntu and Debian feature different modules developed by their vast support communities, so you can select each of these OSs and take advantage of a stable and risk-free hosting service. Based on your selection, you will also have different Control Panels to choose from. Needless to say, we can always replace the Operating System if the one you've selected in the beginning does not meet the requirements of the software which you intend to run. We can also upgrade the OS on a regular basis in order to keep it as risk-free as possible with our Managed Services upgrade package.