Abstract: A fault tolerant/fault resilient computer system includes at least two compute elements connected to at least one controller. Each compute element has clocks that operate asynchronously to clocks of the other compute elements. The compute elements operate in a first mode in which the compute elements each execute a first stream of instructions in emulated clock lockstep, and in a second mode in which the compute elements each execute a second stream of instructions in instruction lockstep. Each compute element may be a multi-processor compute element.

Abstract: A fault tolerant/fault resilient computer system includes at least two compute elements connected to at least one controller. Each compute element has clocks that operate asynchronously to clocks of the other compute elements. The compute elements operate in a first mode in which the compute elements each execute a first stream of instructions in emulated clock lockstep, and in a second mode in which the compute elements each execute a second stream of instructions in instruction lockstep. Each compute element may be a multi-processor compute element.

Abstract: Data transfer to computing elements is synchronized in a computer system that includes the computing elements and controllers that provide data from data sources to the computing elements. A request for data made by a computing element is intercepted and transmitted to the controllers. At least a first controller responds by transmitting requested data to the computing element and by indicating how a second controller will respond to the intercepted request.

Abstract: Synchronized execution is maintained by compute elements processing instruction streams in a computer system including the compute elements and a controller. Each compute element includes a clock that operates asynchronously with respect to clocks of the other compute elements. Each compute element processes instructions from an instruction stream and counts the instructions processed. Upon processing a quantum of instructions from the instruction stream, the compute element initiates a synchronization procedure and continues to process instructions from the instruction stream and to count instructions processed from the instruction stream. The compute element halts processing of instructions from the instruction stream after processing an unspecified number of instructions from the instruction stream in addition to the quantum of instructions. Upon halting processing, the compute element sends a synchronization request to the controller and waits for a synchronization reply.

Abstract: Data transfer to computing elements is synchronized in a computer system that includes the computing elements and controllers that provide data from data sources to the computing elements. A request for data made by a computing element is intercepted and transmitted to the controllers. At least a first controller responds by transmitting requested data to the computing element and by indicating how a second controller will respond to the intercepted request.