Which one of the following is not an operating system?

Correct — D, MS-Excel. An operating system is the layer of software that sits between the hardware and everything else — it schedules programs, allocates memory, manages files and devices, and provides the interface a user works through. MS-Windows is one; Linux is another; and Ubuntu is a distribution built on the Linux kernel, so it too is an operating system in its own right. MS-Excel is none of these. It is application software, a spreadsheet program that has to be installed on top of an operating system and cannot run without one.

• (a)MS-Windows — The most widely used desktop operating system there is. Sharing the MS prefix with Excel is what makes this pair worth reading carefully, but Windows manages the machine while Excel merely runs on it.
• (b)Linux — Linux is the kernel at the heart of a large family of operating systems, first released by Linus Torvalds in 1991, and it runs everything from servers to Android phones.
• (c)Ubuntu — Ubuntu is a complete operating system — a Debian-based Linux distribution. An unfamiliar name is not the same as a different category, and this is the option most often picked by elimination for the wrong reason.

Software divides into system software and application software. System software runs the machine, and the operating system is its centrepiece, handling process scheduling, memory allocation, file storage, device drivers and the user interface. Application software does the user's work — word processing, spreadsheets, browsers, media players — and depends on the operating system underneath it for every service it needs.

Two traps are laid here. The first is the shared MS prefix, which tempts a quick reader to keep Windows and Excel in the same box. The second is Ubuntu, which is the least familiar of the four names to most candidates and therefore the natural pick for anyone eliminating by unfamiliarity; in fact it is a fully fledged Linux distribution used widely on servers and desktops. The reliable test is functional rather than nominal — ask what each item needs in order to run. Windows, Linux and Ubuntu boot the machine themselves. Excel needs an operating system already running before it can open at all.

• An operating system manages processes, memory, files and devices and provides the user interface.
• The Linux kernel was first released by Linus Torvalds in 1991 and is the basis of many operating systems.
• Ubuntu is a Debian-based Linux distribution, that is, a complete operating system rather than an application.
• MS-Excel is a spreadsheet program in the Microsoft Office suite and is application software.
• Android is built on the Linux kernel, while iOS is Apple's mobile operating system — both are system software, not applications.

• Grouping Windows and Excel together because both carry the MS prefix.
• Picking the least familiar name, Ubuntu, on the assumption that unfamiliar means different in kind.
• Treating a Linux distribution as if it were only a program rather than a whole operating system.

Asked as an odd-one-out where three options belong to one software category and the fourth to another, with a shared brand prefix planted to mislead.

No directly related past PYQ was found.

• practice — not a real PYQ

  Which one of the following is application software?

  • (a)Android
  • (b)Ubuntu
  • (c)MS-PowerPoint
  • (d)iOS

  Answer(c) MS-PowerPoint — a presentation program; the other three are operating systems.

• practice — not a real PYQ

  Ubuntu is best described as

  • (a)a web browser
  • (b)a Linux-based operating system
  • (c)a database package
  • (d)an antivirus program

  Answer(b) a Linux-based operating system — a Debian-derived distribution used on desktops and servers.