The first of the modern operating systems was introduced by IBM's 360 computer in the early 1970's. The system was named UNICS which was the earliest version of the UNIX system today. The purpose of developing operating systems was to allow multiple users to simultaneously access the CPU and to give an easy-to-use interface that could hide the details of the hardware from the user. From this milestone, the history of operating systems has evolved with advances in computer technologies.
Over the past decade, the PC industry delivered innovative, cost-effective products that have made the personal computer a widely used tool in the office and in the home. Microsoft's DOS appeared in 1981 and quickly dominated this booming market, however, according to the advance of technologies, the earliest forms of DOS could not support the complex hardware and also lose its importance after more operating systems were released.
As more people used computers, the age of "user-friendly" interfaces developed. Microsoft's Windows released in 1983, was the first of the operating system which addressed the feature of the GUI (graphical user interface). Four years later, Windows released its second version which was added new features such as icons and overlapping windows. Today, the new generation of operating systems are more fully featured because they can offer multitasking services, built-in networking, device support, multimedia services, 32-bit based system architecture and others.