If you get a hosting machine of your own, it will operate independently, so it'll have its own Operating System and you can later install server side apps directly or script-driven sites via a hosting Control Panel. Though keeping the Os updated isn't always considered a necessity, it can be a rather important task for a number of reasons. A more modern OS version may have better support for certain hardware, so you may get better performance for the websites and web applications you install. Your server shall also be more safe because updates often include security patches which fix small problems which may allow unauthorized people to access your content. Last, but not least, newer script versions, which are also released for both enhanced security and for additional features, might require a later version of the Os in order to work properly and with their 100 % capabilities.