UNIX IN THE BEGINNING:
Berkeley Software Distribution released the UNIX software from Berkeley. It was in 1969-1970, when Kenneth Thompson, Dennis Ritchie and others at AT&T Bell Labs started creating a small operating system on a little-used PDP-7. The operating system was entitled Unix. the system was modified in the programming language C, in 1972-1973. Their creative thinking turned out as a remarkable decision as Unix came out as first extensively used operating system that could live longer than its original hardware. Additional innovations were further included to the Unix. to some extent, the reason behind this was the teamwork of Bell Labs and the academic community. The revolution was seen in 1979, when Unix came out with "the seventh edition" (V7) version of UNIX. after this, the history of Unix becomes complexes and complicated. The academic society led by Berkeley developed a modified version called the Berkeley Software Distribution.  

REASONS BEHIND THE POPULARITY OF UNIX:
Unix is an operating system. This program acts as a mediator between a user and computer hardware. The program is capable of handling multiple tasks. Multiple jobs were carried out by the CPU switching between them. Switching is done regularly and quickly which help the users to interact with each program while it is running. Consequently, it increases the efficiency by permitting work to complete on time and one would run to another system. If there is any development in the industry, Unix can adopt it and still remains UNIX. C programming language was used in Unix, it was especially developed to support UNIX. It is free from vendors or hardware. It can run on personal computers, super computers, mini computers, workstation, and mainframes. All these reasons makes UNIX a popular program.