Plan 9 (operating system)

Plan 9 is an operating system descended from Unix and developed by Bell Laboratories. It is not a Unix variant, but is very similar. Plan 9 explored several "simplifications" to the original Unix model that improved the experience of using and programming the system, notably in distributed multi-user environments. Plan 9 was a Bell Labs internal project for a number of years, but a public release was made in 1993, followed by a shrink-wrapped version in 1995. Bell lost commercial interest in the project in the later 1990s, and released a third version under a non-free license (but with source code available) in 2000, and finally under a new open source license in 2002. This is the 4th, and current, edition of the system.

Background

Prior to the development of Plan 9, much of the ongoing research and development in operating systems had centered around several "hot" topics; multiprocessing and parallel computing, computer networking, and the idea of "subprograms" known as threads. Eventually it became clear that all operating systems were attempting to add these features at the same time. Development of these features was somewhat difficult, because if the feature under development were to have a bug, its placement inside the operating system's kernel would cause the entire machine to crash and need to be rebooted.

Related Topics:
Multiprocessing - Parallel computing - Computer networking - Kernel

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

In the early 1980s a new concept started to develop, that of the microkernel. The idea of a microkernel is to reduce the kernel to the bare minimum functions shared by all operating systems at their core. This includes such duties as arbitrating access to hardware, memory, and time on the CPU. A complete OS would then be created as a selection of programs running on top of the kernel, known as servers, communicating to each other by passing messages. The advantage to this approach was that it modularized the operating system, as well as allowing those messages to be passed among machines to create a single larger computer.

Related Topics:
Microkernel - Hardware - CPU

~ ~ ~ ~ ~ ~ ~ ~ ~ ~