What is Operating System ?

In computer science operating system or in various English language operating system or OS is a software system that served to make the control and management of hardware and basic system operations, including the software applications like word processing programs and web browsers.


In general, the Operating System software on the first layer is placed on computer memory when the computer starts up. While other software is run after the Operating System is running, and operating systems will perform the core public service to the software. Core public services such as access to the disk, memory management, task scheduling, and user interface. So that each software does not need to perform tasks common core, as can be managed and conducted by the Operating System.The code of tasks and common core is called the "kernel" of a Operating System


If the computer system divided into layers, then the Operating System is the liaison between the layers of hardware and software layers. More than the Operating System to perform all tasks necessary in the computer, and ensure that different applications can run simultaneously with the current. Operating System ensure other software applications can use the memory, perform input and output of other equipment, and have access to the file system. When running several applications simultaneously, then the Operating System skedule the right, so far as possible all running processes get enough time to use the processor (CPU) and do not interfere with each other.


In many cases, the Operating System provides a library of standard functions, which other applications can call functions, so that in each new program, no need to create these functions from scratch.


Operating systems generally consist of several parts:1. Boot mechanism that is putting the kernel in memory2. Kernel, the core of an Operating System3. Command Interpreter or shell, which reads input from the user4. Libraries, which provides basic set of functions and standards that can be invoked by other applications5. Drivers to interact with external hardware, as well as to control them.


Some operating systems allow only one application running at one time (eg DOS), but most of the new operating system allows multiple applications to run simultaneously at the same time. Operating systems are referred to as Multi-tasking Operating System (eg UNIX family of operating systems.) Some operating systems are very large and complex, and its inputs depending on the user input, while the other Operating Systems is very small and made with the assumption that work without human intervention at all. The first type is often referred to as a Desktop OS, while the second type is the Real-Time OS


As an example, which meant that operating systems include Windows, Linux, Free BSD, Solaris, Palm, Symbian, and so forth.