A short background of Unix and Linux and why Linux is used in the operating systems courses.
Unix is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, developed in the 1970s at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and others1.
Linux is a name which broadly denotes a family of free and open-source software operating system distributions built around the Linux kernel. The defining component of a Linux distribution is the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds2.
Linux is a Unix-like and mostly POSIX-compliant computer operating system2. As of May 2015 it is estimated that 96.55% of all web servers runs Linux 3.
Unix has a very long history both in industry and academia. Compared to proprietary operating systems such as Microsoft Windows and Mac OS X detailed information about the design and implementation of Unix and Linux is much easier to find. As a consequence, Unix/Linux is well suited when studying and learning the core principles of operating systems.