Linux
You are free to run whatever operating system you like on your computer. A few employers may use
Linux on their computers because they find it to be more cost-effective or better suited to their needs. Some mobile phones were designed to run
Linux in order to make them cheaper; there is no practical way to install any other operating system on these, since they are burned into a chip, and anything you would want to run on it would have to be heavily modified.
There are, however, a few things that can make it necessary to use Linux. If you have a tremendous and truly spectacular beard you are required to at least have some familiarity with Linux before use of other OSes is legal in some jurisdictions.
