Operating system

In computing, an operating system (OS) is the system software responsible for the direct control and management of hardware and basic system operations. Additionally, it provides a foundation upon which to run application software such as word processing programs and web browsers.

Introduction

Early computers lacked operating systems (see History of operating systems). A human operator would manually load and run programs. When programs were developed to load and run other programs, it was natural to draw their name from the human job they replaced.

Related Topics:
Computer - History of operating systems

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Most current usage of the term "operating system" today, by both popular and professional sources, refers to all the software that is required in order for the user to manage the system and to run third-party application software for that system. That is, the common understanding includes not only the low-level "kernel" that interacts directly with the hardware, but also libraries required by applications as well as basic programs to manipulate files and configure the system.

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The exact delineation between the operating system and application software is not precise, however, and is occasionally subject to controversy. For example, one of the key questions in the United States v. Microsoft antitrust trial was whether Microsoft's Internet Explorer web browser was part of its Windows operating system or if it was a separable piece of application software. As another example, the GNU/Linux naming controversy is, in part, due to disagreement about the relationship between the Linux kernel and the Linux operating system.

Related Topics:
United States v. Microsoft - Antitrust - Internet Explorer - Web browser - Windows - GNU/Linux naming controversy - Linux kernel - Linux

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The lowest level of any operating system is its kernel, the first layer of software loaded into computer memory when it starts up. As the first software layer, all other software that gets loaded after it depends on this software to provide them with various common core services. These common core services include, but are not limited to: disk access, memory management, task scheduling, and access to other hardware devices. Like the term "operating system" itself, the question of what exactly should form the "kernel" is subject to some controversy—with various camps advocating "microkernels", "monolithic kernels", and so on—with debates over whether things like file systems should be included in the kernel.

Related Topics:
Kernel - Memory management - Task scheduling - Hardware devices - File system

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