Abstract: “Per memory” atomic access for a distributed memory multiprocessor architecture is provided by marking bit masks for shared memories to indicate the access privileges of processors to the memories. A processor has access privileges to a shared memory if the bit mask retained for the memory is marked at a bit position reserved for the processor and does not have access privileges if the bit mask is not so marked. A bit mask is permitted to have only one mark at a given time to guarantee that access to each shared memory is atomic.

Abstract: “Per memory” atomic access for a distributed memory multiprocessor architecture is provided by marking bit masks for shared memories to indicate the access privileges of processors to the memories. A processor has access privileges to a shared memory if the bit mask retained for the memory is marked at a bit position reserved for the processor and does not have access privileges if the bit mask is not so marked. A bit mask is permitted to have only one mark at a given time to guarantee that access to each shared memory is atomic.

Abstract: Shadow arrays are configured in a distributed memory multiprocessor architecture to localize memory referencing. As each additional processor becomes active a variable array having dimensions 1×N, including N single instance variables which must be monitored on a “per processor” basis, is configured in a memory local to the additional processor and made locally referenceable. A patchwork of shadow arrays is thereby established in which each additional processor may reference local memory to access its own value set for the N single instance variables. The single instance formatting of the arrays also advantageously facilitates migration from an single processor operating system to a multiprocessor operating system without substantial recoding.