The operating system that I know can be divided into operating systems for PC and operating systems for a smartphone. For PC it is the Microsoft series that used most and there are also a lot of people use IOS which is designed for mac of Apple. And sometimes if we are developers of the system we may get contact to the system called Linux. There are seldom people who will install Linux OS on his or her PC but Linux can be really good OS for servers. Once I needed to choose a cloud server online