Abstract: A computer system provides for both lock-step and free-step processor modes, allowing for an effective tradeoff between performance and data integrity.

Abstract: In one embodiment, a method for repairing a faulty cache element is provided. Once a monitored cache element is determined to be faulty, the system stores the repair information, and cache configuration in an EEPROM or non-volatile memory on the CPU module. Then the computer is rebooted. During the reboot, the faulty cache element is repaired by being swapped out for a spare cache element based on the information stored in the EEPROM or the non-volatile memory.

Abstract: In one embodiment, a CPU cache management system is provided. The CPU management system includes, for example, a CPU chip and cache management logic. The CPU chip include cache elements that are initially in use and spare cache elements that not initially in use. The cache management logic determines whether currently-used cache elements are faulty. If a cache element is determined to be faulty, the cache management logic schedules a reboot of the computer and swaps in a spare cache element for the faulty currently-used cache element during the reboot.

Abstract: A processor can write its state to an external state cache. Thus, in the event of a processor failure, the stored state can be read and assumed, either by the original processor or another processor. Thus, a process can be resumed from the stored state rather than reconstructed from initial conditions.

Abstract: A computer system has redundant I/O interface modules for managing communications between an incorporating computer system and an external system such as a network or multi-port disk array. A redundant I/O interface manager directs communications through one of the redundant I/O interface modules, and switches the communications through the other, e.g., when a failure of the first I/O interface module is detected or predicted. The redundant I/O interface module appears to the operating system of the incorporating system as the first I/O interface module would so the switching is effectively invisible to the operating system.

Abstract: In one embodiment, a cache element allocation method is provided. Each cache element on a CPU is assigned a quality rank based on the error rate of the cache element. If an allocated cache element is deemed to be faulty, the quality rank of the faulty allocated cache element is compared with the quality rank of the non-allocated cache elements. If a non-allocated cache element has a lower quality rank than the allocated cache element, the non-allocated cache element is swapped in for the allocated cache element.

Abstract: In one embodiment, a cache element allocation method is provided. Each cache element on a CPU is assigned a quality rank based on the error rate of the cache element. If an allocated cache element is deemed to be faulty, the quality rank of the faulty allocated cache element is compared with the quality rank of the non-allocated cache elements. If a non-allocated cache element has a lower quality rank than the allocated cache element, the non-allocated cache element is swapped in for the allocated cache element.

Abstract: Systems and methods for conducting processor health-checks are provided. In one embodiment, a method for evaluating the status of a processor is provided. The method includes, for example, initializing and executing an operating system, de-allocating the processor from the available pool or system resources and performing a health-check on the processor while the operating system is executing.

Abstract: Systems and methods for repairing a processor are provided. In one embodiment, a method for repairing a processor is provided that includes, for example, the steps of initializing and executing an operating system, determining that a cache element is faulty, and swapping in a spare cache element for said faulty cache element while the operating system is executing.

Abstract: Systems and methods for conducting processor health-checks are provided. In one embodiment, a method for evaluating the status of a processor is provided. The method includes, for example, initializing and executing an operating system, de-allocating the processor from the available pool or system resources and performing a health-check on the processor while the operating system is executing.

Abstract: In one embodiment, a cache element allocation method is provided. Each cache element on a CPU is assigned a quality rank based on the error rate of the cache element. If an allocated cache element is deemed to be faulty, the quality rank of the faulty allocated cache element is compared with the quality rank of the non-allocated cache elements. If a non-allocated cache element has a lower quality rank than the allocated cache element, the non-allocated cache element is swapped in for the allocated cache element.

Abstract: Systems and methods for repairing a processor are provided. In one embodiment, a method for repairing a processor is provided that includes, for example, the steps of initializing and executing an operating system, determining that a cache element is faulty, and swapping in a spare cache element for said faulty cache element while the operating system is executing.

Abstract: One embodiment disclosed relates to a high-availability cluster apparatus having a plurality of computing nodes and a hardware interface configured to connect to each of said nodes. The internode connections are coupled to the hardware interface to communicate node status signals between said nodes. A node is removable from being connected to the hardware interface without interrupting a topological continuity of the internode connections. Other embodiments are also disclosed.

Abstract: One embodiment disclosed relates to a high-availability (HA) cluster system. The cluster includes a plurality of computing nodes and clustering software configured to manage the cluster. In addition, the cluster includes a smart card, including a microprocessor-based system, communicatively connected to each of the nodes. Another embodiment disclosed relates to an apparatus adapted for use with a corresponding node of a high-availability (HA) cluster. The apparatus includes a microprocessor, control software, at least one input channel to receive data from the corresponding node, at least one output channel to send commands to the corresponding node, at least one input link to receive commands from clustering software of the HA cluster, and at least one output link to send information to the clustering software. Other embodiments are also disclosed.

Abstract: One embodiment disclosed relates to a method of preventative maintenance of a high-availability cluster. A least-recently-tested active node is determined. The least-recently-tested active node is swapped out from the HA cluster, and a stand-by node is swapped into the HA cluster. Other embodiments are also disclosed.

Abstract: In one embodiment of the invention, a computer readable medium, comprising executable instructions for controlling application of an error correction code (ECC) algorithm in a memory subsystem, comprises code for recording occurrences of data corruption in data retrieved from the memory subsystem, code for analyzing the occurrences of data corruption to detect a repeated bit pattern of data corruption across different addresses of the memory subsystem, and code for controlling application of the ECC algorithm to erase bits associated with a repeated bit pattern, detected by the code for analyzing, from data retrieved from the memory subsystem.

Abstract: In one embodiment, a system comprises non-volatile memory storing a page deallocation table (PDT), a memory controller for storing and retrieving data from a memory subsystem, the memory controller using an error correction code (ECC) algorithm to correct data corruption in retrieved data, a processor for executing an error analysis algorithm, the error analysis algorithm recording instances of data corruption in the PDT, deallocating memory regions associated with multiple occurrences of data corruption at single bit locations, the error analysis algorithm causing the memory controller to apply an erasure mode of the ECC algorithm upon detection of a repeated pattern of data corruption across different addresses of the memory subsystem, and removing entries in the PDT that correspond to data corruption addressed by application of the erasure mode.

Abstract: In one embodiment, a computer readable medium comprises code for recording occurrences of data corruption in data retrieved from a memory subsystem, code for determining whether bit locations within the memory subsystem are associated with multiple occurrences of data corruption, code for deallocating, in response to the code for determining, memory regions containing bit locations associated with multiple occurrences of data corruption, code for analyzing patterns of data corruption repeated across multiple addresses of the memory subsystem, and code for controlling application of an error correction code (ECC) algorithm by the memory subsystem to erase bits associated with a repeated bit pattern, detected by the code for analyzing, from data retrieved from the memory subsystem.

Abstract: Methodology, systems and media associated with selectively allocating memory are described. One exemplary method embodiment comprises receiving a quality data that identifies the quality of one or more allocatable subsets of a memory and selectively allocating a subset of memory from the allocatable memory to an application based, at least in part, on memory quality as identified in the quality data.

Abstract: One embodiment disclosed relates to a node system of a high-availability cluster. The node system includes at least a first register and an output port. The first register stores multi-state status data of the node, and the output port sends signals representing this multi-state status data. The multi-state status data includes at least one degraded state. The node system may also include a second register and an input port. The input port receives signals representing the multi-state status data of another node. The second stores this multi-state status data from the other node. Another embodiment disclosed relates to a method of status reporting for a node of a cluster. A set of rules is applied to determine current multi-state status of the node. The states of the multi-state status including a good state, a bad state, and at least one degraded state.