Which of the following is not an operating system?

Concept

An operating system (OS) is the system software that manages a computer’s hardware (memory, storage, processing) and provides the platform on which other programs run. Application software, by contrast, is installed on top of an OS to let a user accomplish a specific task, such as writing a document — it does not manage hardware itself.

Application

Mac OS, Linux, and Microsoft Windows are each a complete operating system: they boot the machine, manage memory and files, and provide the environment in which other software (including office applications) is installed and executed.

MS Word, however, is a word-processing application that must be installed on top of one of these operating systems (Windows, Mac OS, or a Linux-compatible alternative) — it depends on an OS to run and cannot itself manage a computer’s hardware.

Cross-check

• Mac OS — Apple’s operating system for Macintosh hardware.

• Linux — an open-source, Unix-like operating system kernel used on servers, desktops, and devices.

• Microsoft Windows — Microsoft’s operating system for PC hardware.

• MS Word — a word-processing application from the Microsoft Office suite; it runs on top of an OS rather than managing hardware.

So among the four, MS Word is the one that is not an operating system.