Abstract: A memory subsystem with a memory bus and a memory assembly. The memory bus includes multiple bitlanes. The memory assembly is in communication with the memory bus and includes instructions for receiving an error code correction (ECC) word in multiple packets via the memory bus. The ECC word includes data bits and ECC bits arranged into multiple multi-bit ECC symbols. Each of the ECC symbols is associated with one of the bitlanes on the memory bus. The memory assembly also includes instructions for utilizing one of the ECC symbols to perform error detection and correction for the bits in the ECC word received via the bitlane associated with the ECC symbol.

Abstract: A method, system and computer program product implement memory performance management and enhanced memory reliability of a computer system accounting for system thermal conditions. When a primary memory temperature reaches an initial temperature threshold, reads are suspended to the primary memory and reads are provided to a mirrored memory in a mirrored memory pair, and writes are provided to both the primary memory and the mirrored memory. If the primary memory temperature reaches a second temperature threshold, write operations to the primary memory are also stopped and the primary memory is turned off with DRAM power saving modes such as self timed refresh (STR), and the reads and writes are limited to the mirrored memory in the mirrored memory pair. When the primary memory temperature decreases to below the initial temperature threshold, coherency is recovered by writing a coherent copy from the mirrored memory to the primary memory.

Abstract: A system and method for providing a memory device having a shared error feedback pin. The system includes a memory device having a data interface configured to receive data bits and CRC bits, CRC receiving circuitry, CRC creation circuitry, a memory device pad, and driver circuitry. The CRC receiving circuitry utilizes a CRC equation for the detection of errors in one or more of the received data and the received CRC bits. The CRC creation circuitry utilizes the CRC equation for the creation of CRC bits consistent with data to be transmitted to a separate device bits. The memory device pad is configured for reporting of any errors detected in the received data and the received CRC bits. The driver circuitry is connected to the memory device pad and merged with one or more other driver circuitries resident on one or more other memory devices into an error reporting line.

Abstract: A hub device, memory system, and method for providing a cascade interconnect memory system with enhanced reliability. The hub device includes an interface to a high-speed bus for communicating with a memory controller. The memory controller and the hub device are included in a cascade interconnect memory system and the high-speed bus includes bit lanes and one or more clock lanes. The hub device also includes a bi-directional fault signal line in communication with the memory controller and readable by a service interface. The hub device also includes a fault isolation register (FIR) for storing information about failures detected at the hub device, the information including severity levels of the detected failures. In addition, the hub device includes error recovery logic for responding to a failure detected at the hub device.

Abstract: A system and method for providing a cyclical redundancy code (CRC) for use in a high-speed serial link. The system includes a cascade interconnect memory system including a memory controller, a memory hub device and a downstream link. The downstream link is in communication with the memory controller and the memory hub device and includes at least thirteen signal lanes for transmitting a multiple transfer downstream frame from the memory controller to the memory hub device. A portion of the downstream frame includes downstream CRC bits to detect errors in the downstream frame. The downstream CRC bits capable of detecting any one of a lane failure, a transfer failure and up to five bit random errors.

Abstract: A system to improve error code decoding using historical information. An example system includes storage partitioned into memory ranks, and a table to record symbols having failures for each memory rank. The system generates a memory rank score for each memory rank. The system also includes an error control decoder that uses the memory rank score when each memory rank is accessed in order to determine whether an error should be corrected or not.

Abstract: A system to improve miscorrection rates in error control code may include an error control decoder with a safe decoding mode that processes at least two data packets. The system may also include a buffer to receive the processed at least two data packets from the error control decoder. The error control decoder may apply a logic OR operation to the uncorrectable error signal related to the processing of the at least two data packets to produce a global uncorrectable error signal. The system may further include a recipient to receive the at least two data packets and the global uncorrectable error signal.

Abstract: A system to improve memory reliability in computer systems that may include memory chips, and may rely on a error control encoder to send codeword symbols for storage in each of the memory chips. At least two symbols from a codeword are assigned to each memory chip and therefore failure of any of the memory chips could affect two symbols or more. The system may also include a table to record failures and partial failures of the codeword symbols for each of the memory chips so the error control encoder can correct subsequent partial failures based upon the previous partial failures. The error control coder is capable of correcting and/or detecting more errors if only a fraction of a chip is noted in the table as having a failure as opposed to a full chip noted as having a failure.

Abstract: A memory subsystem with a memory bus and a memory assembly. The memory bus includes multiple bitlanes. The memory assembly is in communication with the memory bus and includes instructions for receiving an error code correction (ECC) word in multiple packets via the memory bus. The ECC word includes data bits and ECC bits arranged into multiple multi-bit ECC symbols. Each of the ECC symbols is associated with one of the bitlanes on the memory bus. The memory assembly also includes instructions for utilizing one of the ECC symbols to perform error detection and correction for the bits in the ECC word received via the bitlane associated with the ECC symbol.

Abstract: A system and method for error correction and detection in a memory system. The system includes a memory controller, a plurality of memory modules and a mechanism. The memory modules are in communication with the memory controller and with a plurality of memory devices. The mechanism detects that one of the memory modules has failed possibly coincident with a memory device failure on an other of the memory modules. The mechanism allows the memory system to continue to run unimpaired in the presence of the memory module failure and the memory device failure.

Abstract: A system and method for providing a high fault tolerant memory system. The system includes a memory system having a memory controller, a plurality of memory modules and a mechanism. The plurality of memory modules are in communication with the memory controller and with a plurality of memory devices. The plurality of memory devices include at least one spare memory device for providing memory device sparing capability. The mechanism is for detecting that one of the memory modules has failed possibly coincident with a memory device failure on an other of the memory modules. The mechanism allows the memory system to continue to run unimpaired in the presence of the memory module failure and the possible memory device failure.

Abstract: A system to improve miscorrection rates in error control code may include an error control decoder with a safe decoding mode that processes at least two data packets. The system may also include a buffer to receive the processed at least two data packets from the error control decoder. The error control decoder may apply a logic OR operation to the uncorrectable error signal related to the processing of the at least two data packets to produce a global uncorrectable error signal. The system may further include a recipient to receive the at least two data packets and the global uncorrectable error signal.

Abstract: A system to improve memory reliability in computer systems that may include memory chips, and may rely on a error control encoder to send codeword symbols for storage in each of the memory chips. At least two symbols from a codeword are assigned to each memory chip and therefore failure of any of the memory chips could affect two symbols or more. The system may also include a table to record failures and partial failures of the codeword symbols for each of the memory chips so the error control encoder can correct subsequent partial failures based upon the previous partial failures. The error control coder is capable of correcting and/or detecting more errors if only a fraction of a chip is noted in the table as having a failure as opposed to a full chip noted as having a failure.

Abstract: A system to improve error code decoding using historical information may include storage partitioned into memory ranks, and a table to record symbols having failures for each memory rank. The system may also generate a memory rank score for each memory rank. The system may also include an error control decoder that may use the memory rank score when each memory rank is accessed in order to determine whether an error should be corrected or not.

Abstract: Systems, methods and computer program products for providing a nested two-bit symbol bus error correcting code. Methods include constructing a nested error correcting code (ECC) scheme. The method includes receiving a Hamming distance n code. A symbol correcting code H-matrix is created by iteratively adding rows of H-matrix bits on a symbol column basis such that the symbol correcting code H-matrix describes a symbol correcting code, and the Hamming distance n code is preserved as a subset of the symbol correcting code H-matrix.

Abstract: Systems and methods for improving serviceability of a memory system including a method for identifying a failing memory element in a memory system when two or more modules operate in unison in response to a read request. The method includes receiving syndrome bits and an address associated with an uncorrectable error (UE). In response to a previous correctable error (CE) having occurred, the location of the previous CE is retrieved. The location of the CE specifies a memory device position of the CE. A location of the UE is determined using the location of the previous CE and the syndrome bits of the UE as input. The location of the UE specified a memory device position. A failing memory element associated with the location of the UE is identified.

Abstract: Systems, method, and computer program products for utilizing a spare lane for additional checkbits. Systems include computer, storage or communications systems with bitlanes for transferring error correcting code (ECC) words in packets over a bus in multiple cycles, a spare bitlane available to the bus, a spared mode and an initial mode. The spared mode is executed when the spare bitlane has been deployed as a replacement bitlane for carrying data for one of the other bitlanes. The initial mode is executed when the spare bitlane has not been deployed as a replacement bitlane. The initial mode includes utilizing the spare bitlane for carrying one or more additional ECC checkbits. The initial mode provides at least one of a more robust error detecting function for the bus than the spared mode and a more robust error correcting function for the bus than the spared mode.

Abstract: A hub device, memory system, and method for providing a cascade interconnect memory system with enhanced reliability. The hub device includes an interface to a high-speed bus for communicating with a memory controller. The memory controller and the hub device are included in a cascade interconnect memory system and the high-speed bus includes bit lanes and one or more clock lanes. The hub device also includes a bi-directional fault signal line in communication with the memory controller and readable by a service interface. The hub device also includes a fault isolation register (FIR) for storing information about failures detected at the hub device, the information including severity levels of the detected failures. In addition, the hub device includes error recovery logic for responding to a failure detected at the hub device. Responding to the error includes recording a severity level of the failure in the FIR and taking an action at the hub device that is responsive to the severity level of the failure.

Abstract: A system and method for providing a cyclical redundancy code (CRC) for use in a high-speed serial link. The system includes a cascade interconnect memory system including a memory controller, a memory hub device and a downstream link. The downstream link is in communication with the memory controller and the memory hub device and includes at least thirteen signal lanes for transmitting a multiple transfer downstream frame from the memory controller to the memory hub device. A portion of the downstream frame includes downstream CRC bits to detect errors in the downstream frame. The downstream CRC bits capable of detecting any one of a lane failure, a transfer failure and up to five bit random errors.

Abstract: A system and method for providing a memory device having a shared error feedback pin. The system includes a memory device having a data interface configured to receive data bits and CRC bits, CRC receiving circuitry, CRC creation circuitry, a memory device pad, and driver circuitry. The CRC receiving circuitry utilizes a CRC equation for the detection of errors in one or more of the received data and the received CRC bits. The CRC creation circuitry utilizes the CRC equation for the creation of CRC bits consistent with data to be transmitted to a separate device bits. The memory device pad is configured for reporting of any errors detected in the received data and the received CRC bits. The driver circuitry is connected to the memory device pad and merged with one or more other driver circuitries resident on one or more other memory devices into an error reporting line.