If you get a hosting machine of your own, it will run independently, so it'll have its own Os and you'll be able to later install server side apps directly or script-driven sites through a hosting Control Panel. While keeping the Os updated is not always considered a necessity, it can be a really important task for a number of reasons. A newer OS version could have better support for specific hardware, so you might get better performance for the sites and web apps which you install. Your server will also be more secure since updates normally include security patches which fix small problems that may allow unauthorized individuals to access your content. Last, but not least, more modern script versions, which are also released for both improved security and for additional features, may require a later version of the Os in order to work properly and with their full capabilities.