Abstract: A distributed software system and method are provided for use with a plurality of potentially heterogeneous computer machines connected as a network. The system may comprise at least one agent comprising a protection domain, wherein the protection domain of the at least one agent resides on at least two of the plurality of computer machines. A plurality of objects is contained within the protection domain of the at least one agent, a first object residing on a first of the at least two computer machines and a second object residing on a second of the at least two computer machines. The objects are selectively movable among the at least two computer machines by a programmer of the system.

Abstract: The system comprises a collection of address spaces within which potentially many concurrent lightweight perceptible threads may execute. The address space is uniformly distributed among different nodes in a network of heterogeneous machines. Address spaces are first-class and may be generated dynamically. Threads within an address space may communicate with one another via shared memory; communication between address spaces takes place using explicit message-passing.

Abstract: A computer software architecture for controlling a highly parallel computer system comprises several layers of abstraction. The first layer is an abstract physical machine which contains a set of abstract physical processors. This layer may be considered as a microkernel. The next layer includes virtual machines and virtual processors. A virtual machine comprises a virtual address space and a set of virtual processors that are connected in a virtual topology. Virtual machines are mapped onto abstract physical machines with each virtual processor mapped onto an abstract physical processor. The third layer of abstraction defines threads. Threads are lightweight processes that run on virtual processors. In a preferred embodiment the abstract physical machines, abstract physical processors, virtual machines, virtual processors, thread groups, and threads are all first class objects.