Operating+Systems

[|What is an Operating System?]
An operating system is a software controlling the operation of a computer system and its resources. Major functions of operating systems may include: Not all operating systems provide all of these functions. Single-tasking systems like MS-DOS would not schedule processes, while embedded systems like eCOS may not have a user interface. An operating system is *not*: While most operating systems are distributed with such tools, they are not themselves a necessary part of the OS. Some operating systems, such as Linux, may come in several different packaged forms, called _distributions_, which may have different suites of applications and utilities, and may organize some aspects of the system differently. Nonetheless, they are all versions of the same basic OS, and should not be considered to be separate types of operating systems. Current (2011) operating systems include: There have been many other operating systems in the past, and many others currently which are not listed here. At any given time there are several projects to develop new operating systems in the works.
 * Managing memory and other system resources.
 * Managing and directing device drivers.
 * Imposing security and access policies.
 * Scheduling and multiplexing processes and threads.
 * Launching and closing user programs, and providing basic system services for them.
 * Providing a basic user interface and application programmer interface.
 * The computer hardware.
 * A specific application such as a word processor, web browser or game.
 * A suite of utilities (like the GNU tools, which are used in many Unix-derived systems).
 * A development environment (though some OSes, such as UCSD Pascal or Smalltalk-80, incorporate an interpreter and IDE).
 * A Graphical User interface (though many modern operating systems incorporate a GUI as part of the OS).
 * Windows
 * MacOS X
 * Linux
 * FreeBSD
 * SkyOS
 * Plan 9