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