The operating system (OS), including the kernel, is the most basic part of the software. The two main flavours of operating systems are MS-DOS and Unix. MS-DOS has evolved into Windows and is mainly used on desktop systems. Unix branched into many flavours of operating systems for dekstops, mobile phones and servers. Two main branches of Unix-based operating systems are Apple and Linux. The latter spawned Android. Linux comes in a family of slightly different tastes, such as Redhat, SUSE, Fedora, CentOS, Debian and more. Ubuntu is a popular child of Debian parent. It has a history of ongoing development and long term support (LTS) versions.
