Command line interface (or CLI) OS's such as DOS, use only the keyboard for input. Modern OS's use a mouse for input with a graphical user interface (GUI) sometimes implemented as a shell. The appropriate OS may depend on the hardware architecture, specifically the CPU, with only Linux and BSD running on almost any CPU. Since the early 1990s the choice for personal computers has been largely limited to the Microsoft Windows family and the Unix-like family, of which Linux and Mac OS X are becoming the major choices. Mainframe computers and embedded systems use a variety of different operating systems, many with no direct connection to Windows or Unix, but typically more similar to Unix than Windows.

The Unix-like family is a diverse group of operating systems, with several major sub-categories including System V, BSD, and Linux. The name "Unix" is a trademark of The Open Group which licenses it for use to any operating system that has been shown to conform to the definitions that they have cooperatively developed. The name is commonly used to refer to the large set of operating systems which resemble the original Unix.

Unix systems run on a wide variety of machine architectures. They are used heavily as server systems in business, as well as workstations in academic and engineering environments. Free software Unix variants, such as Linux and BSD, are increasingly popular.

The Microsoft Windows family of operating systems originated as a graphical layer on top of the older MS-DOS environment for the IBM PC. Modern versions are based on the newer Windows NT core that first took shape in OS/2 and borrowed from OpenVMS. Windows runs on 32-bit and 64-bit Intel and AMD computers, although earlier versions also ran on the DEC Alpha, MIPS, and PowerPC architectures (there was work in progress to make it work also on the SPARC architecture)

Decide if the sentences are true (T) or false (F).

1. DOS uses both mouse and keyboard for input.

22. Linux and Mac OS X has become the major choices since the early 1990s.

3. The name "Unix" is a trademark of The Open Group which licenses it for use to any operating system.

4. Programmers prefer to use free software Unix variants.

5. Modern versions of the Microsoft Windows family of operating systems are based on the newer Windows NT core.

VOCABULARY

2. Find the words in the text that mean:

1. a piece of computing equipment with keys on it, used for putting information into a computer.

2. a powerful computer that has a number of smaller computers connected to it for individual users.

3. the software that tells the parts of a computer how to work together and what to do.

4. a powerful computer used in an office or other place of work.

5. a form of something that is different from other forms or from the original.

3. Complete the text with the words in the box.

multimedia computer graphical embedded active

Other operating systems.

Older operating systems which are still used in niche markets include the Windows-like OS/2 from IBM; Mac OS, the non-Unix precursor to Apple's Mac OS X; BeOS, which is still used widely in theatre for sound design; RISC OS, which is specifically designed to run on ARM processor architectures; and AmigaOS, the first user 3. _____________ interface (GUI) based operating system with advanced 4. ____________ capabilities available to the general public.

Research and development of new kinds of operating systems is an active subfield of 5._______________science. Microsoft Singularity is a research project to develop an operating system with better memory protection.

WRITING

4. Describe any OS you know.