What is an Operating System?

Operating systems provide a software platform on top of which other programs, called application programs, can run. The application programs must be written to run on top of a particular operating system. Your choice of operating system, therefore, determines to a great extent the applications you can run. For PCs, the most popular operating systems are DOS, OS/2, and Windows, but others are available, such as Linux.

Types of Operating Systems:-

multi-user : Allows two or more users to run programs at the same time. Some operating systems permit hundreds or even thousands of concurrent users.

multiprocessing : Supports running a program on more than one CPU.

multitasking : Allows more than one program to run concurrently.

multithreading : Allows different parts of a single program to run concurrently.

real time: Responds to input instantly. General-purpose operating systems, such as DOS and UNIX, are not real-time.