An Operating System is the software that interacts with the hardware of a computer system and serves as the intermediary between applications and the hardware, including peripherals such as a printer, a mouse or a keyboard. When you run software, it transfers requests to the OS using an API (Application Program Interface) and the contact is done via a command line or a Graphical User Interface (GUI). Similar to a personal computer, hosting servers also feature an Operating System that serves as a host for any software installed on them, which includes script apps or server-side software such as a flash server, a VOIP server, and many others. A virtual machine can be generated on a physical one, so it is possible to install a guest OS on it and have a different system environment in contrast to the physical server host Operating System.
