Operating System

Operating system

Introduction

An operating system is a program or set of programs on a computer system that manages the resources of hardware and provides services to application programs, running in privileged mode on the other. One purpose of operating system is to manage the intermediary is to manage the location and resources of the hardware access protection, a fact that relieves application programmers from having to deal with these details. In computing, an operating system is a collection of programs that manages the use of the capabilities of a computer with software applications. It receives from the application software applications using the capabilities of the computer - storage capacity of memory and hard drives, computing capacity of the processor. The operating system accepts or rejects such requests and reserve resources in question to ensure that their use does not interfere with other applications from other software (gcflearnfree.org).

The operating system is the first program executed when starting the computer, after the boot. It offers a suite of services that facilitate the general development of software applications and acts as an intermediary between the software and hardware. An operating system brings convenience, efficiency and scalability, allowing introducing new features and new hardware without compromising software. There are on the market for dozens of different operating systems. They often come with the computing device - this is the case of Windows, Mac OS, Irix and Symbian OS. The features offered differ from one model to another, and are typically related to the implementation of programs, the use of main memory, the devices, the handling of file system, communication, or detection of errors.

The operating system provides a suite of services that facilitate the general development of software applications. Services are related to the use of resources of the computer by the program. They allow in particular running programs, reading and writing information, manipulate files, communicate between computers and detect errors. These services allow multiple users and multiple programs to share computer resources. The operating system ensures the reservation of various resources for the needs of programs, which are executed simultaneously. Reservations can be included in activity logs for statistical purposes or for troubleshooting and operating system can refuse a booking for a user who has not received prior authorization. From the point of view of the programmer, the application software looks down in the direction of the operating system and the hardware and programs are considered running on the operating system. An operating system can be seen as a virtual machine. The set consists of hardware and operating system as the "machine" that executes the application software, a machine part simulated by software (kristoffer.vinther.name/academia).

Von Neumann model

The Von Neumann architecture (VNA) is a reference model for computer, after which a joint store both computer program instructions and data holds. Von Neumann systems belong to the classification to the class of SISD architectures (single instruction, single data), in contrast to parallel processing. The Von Neumann architecture is a circuit concept for realizing universal computer (von Neumann computer, ...