The development of operating systems has gone through 4 stages.
The first generation of electron tube computers was born in the 1940s, when operating systems did not yet exist and programmers dealt directly with the hardware.
The second generation of transistor computers began in the 1950s, in order to improve the efficiency of the use of computing resources and reduce idle time, a single-pass batch system was proposed; in the 1960s, with the development of small-scale integrated circuits, a multi-channel batch operating system appeared in order to further improve the efficiency of the use of resources; in the 1970s, large-scale integrated circuits developed rapidly. A hundred operating systems have emerged, such as UNIX, DOS, Windows, Mac OS, Linux and other famous operating systems.
The third generation is the era of application operating systems represented by Android and ios, where applications become the main tools for managing content. Between the content and the operating system, a layer is separated, and the application replaces the operating system to realize the function of managing the content more conveniently and effectively. And the way the content is presented is also presented in the way of application, and users no longer have direct contact with the content itself.
The fourth generation is the embedded operating system is the operating system applied to the embedded system. Embedded systems are widely used in all aspects of life, covering a range from portable devices to large fixed facilities, such as digital cameras, cell phones, tablet computers, home appliances, medical equipment, traffic lights, avionics and factory control equipment, etc. More and more embedded systems are installed with real-time operating systems.