Unix originated as a stripped down version of MULTICS created by Ken Thompson on a PDP-7 minicomputer in the 1970s. It was written in assembly language initially but later rewritten in C by Thompson and Dennis Ritchie. POSIX standards were developed to ensure portability across Unix systems. Windows started as the command-line MS-DOS operating system in the 1980s and later added a graphical user interface called Windows. It has continued adding features and versions over time to become the dominant desktop operating system, including Windows 95, 98, 2000, and NT. In conclusion, the document compares that Unix is free and open source while Windows is proprietary, Unix can run on more system varieties, and Unix has a