Distributed operating systems (OSs) are a type of network operating system (NOS). NOSs exist mostly or fully for, their main reason for being, is to facilitate networking, between two or more computers, to operate and improve networks, with non-trivial networking (e.g., routing) included and/or built in, which need not be added later, and they make little sense without their network functions. Many OSs have some networking ability, but not all such OSs are NOSs. Distributed OSs go beyond most NOSs, to divide, distribute, and even dynamically migrate tasks and information, to operate, over networks to run on two or more processors, often called clustering, and heterogeneous multiprocessing. By definition, distributed OSs are multiprocessor OSs, usually asymmetric. On this page, OSs are arranged in two groups and levels: 1) Top group: OSs for which there are more than one instance of an OS of this name/type, an OS family. 2) Bottom group: specific OSs, individual instances; there is only one OS of this name/type.


The 2K distributed operating system (OS) seeks to modify the way traditional systems interact with application software, to accommodate different service requirements and dynamic changes in rapidly evolving, heterogeneous environments. By maintaining an explicit representation of the dependencies between system and application components, the OS infrastructure can better configure the system (optimizing its performance) and recognize the need for reconfiguration. It can know how to carry out this (re)configuration without compromising system stability, performance, and reliability. High-level 2K systems are built atop a dynamically configurable CORBA ORB named dynamicTAO. The system exports a homogeneous view to its users and can be run on extant OSs (Linux, Solaris, Windows, ...), and on the specialized Off++ microkernel.
Plan 9 is an operating system (OS) with some new perspectives and features from the original developers of Unix, who worked at AT&T Bell Labs, and then Lucent Technologies. It continues the main Unix ideas and takes them to their logical conclusions. It has been fully open source since the 4th Edition release.