Definitions Edit

Operating system software (also operating system or OS) is

a special collection of computer programs that has two primary purposes. First, operating systems provide the interface between application programs and the CPU and other hardware components. Second, operating systems load and run other programs.[1]
is the group of programs that monitor and control the operation of the computer system while the application programs are running.[2]
[t]he software 'master control application' that runs the computer. It is the first program loaded when the computer is turned on, and its main component, the kernel, resides in memory at all times. The operating system sets the standards for all application programs (such as the Web server) that run in the computer. The applications communicate with the operating system for most user interface and file management operations.[3]

Overview Edit

"All operating systems include one or more command processors that allow users to type commands and perform tasks like running a program or printing a file."[4]

Operating systems can be classified as follows:

Application programs make use of the capabilities that the operating system provides. For example, computer programs read and write files by using built-in capabilities of the operating system.

Operating systems include some built-in security features like user names, passwords, and permissions, to perform specific tasks, such as running certain applications or accessing specific information such as a file or a database.

Most operating systems also include a graphical user interface that enables the user to perform most tasks by clicking on-screen icons. Some examples of operating systems are Microsoft Windows, Unix, Linux, OS/390, z/OS, and Mac OS.

How they work Edit

An OS is loaded into a computer by a boot program and then manages all the other programs (i.e., applications, services, or application-enabling programs such as middleware) running on the computer. All computers, from small embedded processors to large servers supporting tens of thousands of users, require an OS. Most OSs have been designed and implemented to provide a wide range of features and services.

References Edit

  1. Technology Assessment: Cybersecurity for Critical Infrastructure Protection, at 141.
  2. Information Technology: Tools and Techniques for Improving the Efficiency of Federal Automatic Data Processing Operation, at 19.
  3. NISTIR 7621 Rev. 1, at A-2.
  4. Id.

See also Edit

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