A couple interesting projects along these lines are Barrelfish ( http://www.barrelfish.org/ http://www.barrelfish.org/ ) and Helios ( http://research.microsoft.

A couple interesting projects along these lines are Barrelfish ( http://www.barrelfish.org/ http://www.barrelfish.org/ ) and Helios ( http://research.microsoft.com/apps/pubs/?id=81154 http://research.microsoft.com/apps/pubs/?id=81154 http://research.microsoft.com/pubs/81154/helios.pdf http://research.microsoft.com/pubs/81154/helios.pdf ). Both projects put a lot of focus on being an operating system for a heterogeneous system (with several types or architectures of CPU, a GPU, maybe a NIC that acts as a first-class citizen rather than a slave, etc.), but the architecture they developed to make that work also works well for making the operating system functional on a CMP without cache coherence. As for "pure-functional," that is difficult to achieve in many cases since one of the operating system's main purposes is to help programs have side effects, but I think "shared-nothing" and "distributed-system-like" are good aims for an OS that works on an incoherent CMP.