The appearance of 64-bit processors allows a new approach to microkernel desagn From our experience with a message passang microkernel MESHIX, we discovered that a multi-address space, POSIX architecture is unsvttable for general parallel applications development Angel was therefore deszgned to provide a more flexible envtronmeni. Central to these arms is a simplzficataon of resources. This 1s achaeved through the use of a single address space holding all data and processes, and which absorbs communicatton to remove the distinction between local and remote machanes The result is a kernel scalable to massively parallel machines whzlst maintaaning the shared vartable paradigm.