Abstract: A method and system are disclosed for detecting memory chip failure in a computer memory system. The method comprises the steps of accessing user data from a set of user data chips, and testing the user data for errors using data from a set of system data chips. This testing is done by generating a sequence of check symbols from the user data, grouping the user data into a sequence of data symbols, and computing a specified sequence of syndromes. If all the syndromes are zero, the user data has no errors. If one of the syndromes is non-zero, then a set of discriminator expressions are computed, and used to determine whether a single or double symbol error has occurred. In the preferred embodiment, less than two full system data chips are used for testing and correcting the user data.

Abstract: Methods and apparatus perform fault isolation in multiple node computing systems using commutative error detection values for—example, checksums—to identify and to isolate faulty nodes. When information associated with a reproducible portion of a computer program is injected into a network by a node, a commutative error detection value is calculated. At intervals, node fault detection apparatus associated with the multiple node computer system retrieve commutative error detection values associated with the node and stores them in memory. When the computer program is executed again by the multiple node computer system, new commutative error detection values are created and stored in memory. The node fault detection apparatus identifies faulty nodes by comparing commutative error detection values associated with reproducible portions of the application program generated by a particular node from different runs of the application program. Differences in values indicate a possible faulty node.

Abstract: A low latency memory system access is provided in association with a weakly-ordered multiprocessor system. Each processor in the multiprocessor shares resources, and each shared resource has an associated lock within a locking device that provides support for synchronization between the multiple processors in the multiprocessor and the orderly sharing of the resources. A processor only has permission to access a resource when it owns the lock associated with that resource, and an attempt by a processor to own a lock requires only a single load operation, rather than a traditional atomic load followed by store, such that the processor only performs a read operation and the hardware locking device performs a subsequent write operation rather than the processor. A simple prefetching for non-contiguous data structures is also disclosed.

Abstract: The present invention concerns methods and apparatus for performing fault isolation in multiple node computing systems using commutative error detection values—for example, checksums—to identify and to isolate faulty nodes. In the present invention nodes forming the multiple node computing system are networked together and during program execution communicate with one another by transmitting information through the network. When information associated with a reproducible portion of a computer program is injected into the network by a node, a commutative error detection value is calculated and stored in commutative error detection apparatus associated with the node. At intervals, node fault detection apparatus associated with the multiple node computer system retrieve commutative error detection values saved in the commutative error detection apparatus associated with the node and stores them in memory.

Abstract: A trace cover suitable for shielding a conductive trace on a top layer of a circuit board. The trace cover includes a dielectric body disposed substantially over the conductive trace, side shielding perpendicular to the direction of the conductive trace and substantially parallel to the length of the conductive trace, and top shielding disposed on the top surface of the body. The side shielding and top shielding are electrically coupled with the at least one circuit ground of the circuit board.