Understanding where and how Unix developed may help you to understand some of the concepts in Linux. After all Linux is UNIX like os.
Unix was originally developed in the Computing Sciences Research Center at Bell Telephone Laboratories. The first version was developed in 1970. Read this article for more information on UNIX history. From the site, “After three decades of use, the UNIX* computer operating system from Bell Labs is still regarded as one of the most powerful, versatile, and flexible operating systems (OS) in the computer world. Its popularity is due to many factors, including its ability to run a wide variety of machines, from micros to supercomputers, and its portability — all of which led to its adoption by many manufacturers.
Like another legendary creature whose name also ends in ‘x,’ UNIX rose from the ashes of a multi-organizational effort in the early 1960s to develop a dependable timesharing operating system”
Read this page. The uniqueness of UNIX mentioned here applies to Linux as well. Especially two flash animations makes idea clear.
Read the article, The Creation of the UNIX* Operating System @ Bell Labs.