Plan 9 is an operating system kernel with an available collection of software, originally developed at Bell Labs.
Plan 9 from Bell Labs is a research system developed at Bell Labs starting in the late 1980s. Its original designers and authors were Ken Thompson, Rob Pike, Dave Presotto, and Phil Winterbottom. They were joined by many others as development continued throughout the 1990s to the present.
In Plan 9, each process has its own mutable name space. A process may rearrange, add to, and remove from its own name space without affecting the name spaces of unrelated processes. Included in the name space mutations is the ability to mount a connection to a file server speaking 9P, a simple file protocol. The connection may be a network connection, a pipe, or any other file descriptor open for reading and writing with a 9P server on the other end. Customized name spaces are used heavily throughout the system, to present new resources (e.g., the window system), to import resources from another machine (e.g., the network stack), or to browse backward in time (e.g., the dump file system).
The current available version is the fourth release, whose installation resources and instructions are available here.
