Underware: An Exokernel for the Internet?

The principles for designing and building shared dis- tributed computing environments are still evolving: to- day, there exist a myriad of environments targeting dif- ferent applications serving different user communities. NSF's GENI initiative proposes a new shared environ- ment to serve as an open testbed for designing and build- ing a Future Internet. The design of GENI, along with other distributed computing environments, must confront core OS issues of isolation, coordinated multiplexing of hardware resources, and abstractions for distributed com- puting. This paper draws parallels to the extensible OS "kernel wars" of the past, and considers how architec- tural lessons from that time apply to an Internet OS. Our view echoes, in key respects, the principles of Exokernel a decade ago: the common core of an Internet OS should concern itself narrowly with physical resource manage- ment. We refer to this common core as underware to emphasize that it runs underneathexisting programming environments for distributed computing.