Abstract: Multiple interfaces dedicated to individual logic circuits such as memory arrays are capable of being dynamically reconfigured from operating separately and in parallel to operating in a more collective manner to ensure that data associated with all of the logic circuits will be communicated irrespective of a failure in any of the interfaces. Specifically, a plurality of interfaces, each of which being ordinarily configured to communicate data associated with an associated logic circuit in parallel with the other interfaces, may be dynamically reconfigured, e.g., in response to a detected failure in one or more of the interfaces, to communicate data associated with each of the interfaces over each of at least a subset of the interfaces in a time multiplexed and replicated manner.

Abstract: An apparatus and method is disclosed for providing capacity on demand using control to alter latency and/or bandwidth on a signaling bus in a computer system. If additional capacity is required, authorization is requested for additional capacity. If authorized, bandwidth of the signaling bus is increased to provide additional capacity in the computing system. Alternatively, upon authorization, latency of data transmissions over the signaling bus is reduced. In another alternative, upon authorization, memory timings are adjusted to speed up memory fetches and stores.

Abstract: Methods and apparatus that may be utilized to improve the scalability of multi-processor systems are provided. Data packets constructed in accordance with a defined coherence protocol may be encapsulated in standard I/O packets. As a result, the same interconnect fabric may be used to route coherent data traffic and I/O data traffic.

Abstract: In a first aspect, a first method is provided for efficient memory usage. The first method includes the steps of (1) determining whether data retrieved from a first storage device is characterized as data that is primarily read; and (2) if data retrieved from the first storage device is characterized as data that is primarily read (a) writing the retrieved data in a temporary storage device with short write latency; and (b) writing the retrieved data in a high-density memory. Numerous other aspects are provided.

Abstract: Multiple memory channels of a multi-channel memory architecture are effectively bridged together to enable data traffic associated with various nodes in daisy chain arrangement to be communicated over both memory channels. For example, a daisy chain arrangement of nodes, such as FB-DIMM memory modules disposed in a first memory channel may be coupled to a second memory channel, with support for communicating data associated with one of the nodes over either or both of the first and second memory channels.

Abstract: An apparatus and method is disclosed for flushing a cache in a computing system. In a multinode computing system a cache in a first node may contain modified data in an address space of a second node. The cache in the first node must be purged prior to shutting down the first node. The computing system uses a random class replacement scheme for the cache. A cache flush routine sets a cache flush mode in a class replace select mechanism, overriding the random class replacement scheme. With the random class replacement scheme overridden, a minimum number of fetches will flush all the cache lines in the cache, each fetch loading the cache with a cache line not already in the cache. No additional delay penalty is incurred in a critical path through which fetches and stores to the cache must pass.

Abstract: A diagnostic interface architecture for a memory device supports in one aspect one or more dynamically reconfigurable functional interconnects normally utilized in connection with reading data from the memory device and/or writing data to the memory device. The dynamically reconfigurable functional interconnects are capable of being configured to operate in either functional or diagnostic modes, whereby in the diagnostic mode, such interconnects may be used to communicate diagnostic information to support one or more diagnostic operations. The diagnostic interface architecture may also support multiple diagnostic interfaces in a given memory device, with at least one such diagnostic interface being capable of being selectively enabled in response to a failure in another diagnostic interface.

Abstract: A circuit arrangement, method and apparatus utilize communication links that are selectively configurable to operate in both unidirectional and bidirectional modes to communicate data between multiple nodes that are interconnected to one another in a daisy chain configuration. As a result, in many instances communications may be maintained with nodes located both before and after a discontinuity in a daisy chain configuration.

Abstract: Selectively transmitting cache misses within multiple-node shared-memory systems employing coherence protocols is disclosed. A cache-coherent system includes a number of nodes employing a coherence protocol to maintain cache coherency, as well as memory that is divided into a number of memory units. There is a cache within each node to temporarily store contents of the memory units. Each node further has logic to determine whether a cache miss relating to a memory unit should be transmitted to one or more of the other nodes lesser in number than the total number of nodes within the system. This determination is based on whether, to ultimately reach the owning node for the memory unit, such transmission is likely to reduce total communication traffic among the total number of nodes and unlikely to increase latency as compared to broadcasting the cache miss to all the nodes within the system.

Abstract: Methods and apparatus are disclosed that allow an electronic system having a signaling bus with a fault on a signaling conductor to operate at a degraded performance. A block of data is transferred from a first electronic unit to a second electronic unit over the signaling bus. A transmission sequence sends the block of data using all of the nonfaulty signaling conductors using a minimum number of beats required to complete the transmission.

Abstract: Methods, apparatus, and program product are disclosed for use in a computer system to provide for dynamic allocation of a directory memory in a node memory controller in which one or more coherent multiprocessor nodes comprise the computer system. The directory memory in a node is partitioned between a snoop directory portion and a remote memory directory portion. During a predetermined time interval, snoop directory entry refills and remote memory directory entry refills are accumulated. After the time interval has elapsed, a ratio of the snoop directory entry refills to the number of remote memory directory entry refills is computed. The ratio is compared to a desired ratio. Respondent to a difference between the ratio and the desired ratio, adjustments are made to the allocation of the memory directory between the snoop directory and the remote memory directory.