An operating system, or OS, is a program which directly interacts with a computer's hardware in order to run other programs. Operating systems are required for most modern computers to run. The OS typically loads immediately after the boot loader. In some earlier computers, however, the boot loader was built into the operating system.

Types of operating systems Edit

Microcomputer Edit

Found on microcomputers.

Mini Edit

Generally designed for mini computers and not common today. These are not Unix variants.

Desktop Edit

Designed for personal (i.e., home or office) use. They typically interface with the user graphically, although Linux users commonly prefer the command-line. Desktop operating systems include Windows, Macintosh, and some Unix-like distributions.

Embedded Edit

Included in permanently programmed devices such as microwave ovens, iPods, mobile phones, and thermostats.

Unix-Like Edit

Main article: Unix-like

Derived from Unix or designed to be compatible with Unix. Common Unix-like operating systems include Linux, BSD, and AIX.

Command-Line Driven Edit

Command-line driven operating systems are most common on servers. Some of the older CLIs are directly based off programming languages (like KERNAL), while others had a command interpreter (like MS-DOS). Aside from some Unix variants, most command-line driven operating systems have left the commercial desktop market, because casual users are more familiar with GUIs and find them easier to use.

Graphical Edit

Most modern operating systems use graphical user interfaces because this allows users to navigate computers more easily. The primary disadvantage of GUI-based operating systems is they take a great deal of memory as compared to command line systems. There are also GUIs that run on top of CLI's such as Windows 3.1 and X Window System.