OPERATING SYSTEM

Operating system (commonly abbreviated to OS, O/S or kernel [1]) is an interface between hardware and software in a computer system. The OS is responsible for the management and coordination of activities and the sharing of the limited resources of the computer. The operating system acts as a host for applications that are run on the machine. As a host, main purposes of an operating system are to handle the details of the operation of the hardware. This relieves application programs from having to manage these low level details of hardware and makes it easier to write software. Almost all computers, including handheld computers, desktop computers, supercomputers, and even video game consoles, use an operating system of some type. Some of the oldest models may however use an embedded operating system, that may be contained on a compact disk or other data storage device.
Operating systems offer a number of services to system programs, user interfaces, application programs and hardware. Applications access these services through system calls and Hardware trough device drivers. By invoking system call, the application can request a service from the operating system, pass parameters, and receive the results of the operation. Users may also interact trought the operating system using some kind of software or hardware what offers user interface (UI), like keyboard typing commands to command line interface (CLI) or using a keyboard and mouse with graphical user interface (GUI, commonly pronounced “gooey”).
Common contemporary operating systems include Mac OS, Windows, Linux, BSD and Solaris. While servers generally run on Unix or Unix-like systems, embedded device markets are split amongst several operating systems.[2][3]