OS!

OPERATING SYSTEMS!

OS is know as operating system, an operating system (OS) is system software that manages computer hardware and software resources and provides common services for computer programs. The operating system is a component of the system software in a computer system. Application programs usually require an operating system to function.
For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware,although the application code is usually executed directly by the hardware and frequently makes system calls to an OS function or is interrupted by it. Operating systems are found on many devices that contain a computer—from cellular phones and video game consoles to web servers and supercomputers.
Examples are, ios, blackberry and andriod.

Types of operating systems

1. Single- and multi-tasking.
2. Single- and multi-user.
3. Distributed.
4. Templated.
5. Embedded.
6. Real-time.
7. Library.

Examples of operating systems

1. Unix and Unix like operating systems.
2. BSD and its descendants.
3. Linux.
4. Windows.