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Plan 9 at Bell Labs

Plan 9 was developed by Ken Thompson, Rob Pike, Dave Presotto and Phil Winterbottom.
It was developed to resolve many system problems inherent in Unix systems.
Plan 9 is Unix-like but it is a fresh, completely original kernel.
Most of the software is also original, written specifically for Plan 9.
The Plan 9 operating system is available as an installation cd or a live cd.
It is in active development.