Abstract: A memory subsystem system including a rectangular printed circuit card having a first side and a second side, a length of between 149.5 and 153.5 millimeters, and first and second ends having a width smaller than the length. The memory system also includes a first plurality of pins on the first side extending along a first edge of the card that extends the length of the card, and a second plurality of pins on the second side extending on the first edge of the card. The memory system further includes a positioning key having it center positioned on the first edge of the card and located between 84.5 and 88.5 millimeters from the first end of the card and located between 62.5 and 66.5 millimeters from the second end of the card.

Abstract: Systems and methods for providing a variable frame format protocol in a cascade interconnected memory system. The systems include a memory hub device that utilizes a first bus interface to communicate on a high-speed bus. The hub device also includes frame decode logic for translating variable format frames received via the first bus interface into memory device commands and data. The translating includes identifying write data headers and associated write data for self-registering write to data buffer commands.

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 communication interface device, system, method, and design structure for error correcting code (ECC) protected quasi-static bit communication (SBC) on a high-speed bus are provided. The communication interface device includes high-speed sampling logic to capture high-speed data from the high-speed bus using a high-speed sampling clock and SBC sampling logic to capture SBC samples from the high-speed bus using an SBC sampling clock. The SBC sampling clock is slower than the high-speed sampling clock. The communication interface device also includes an SBC finite state machine (FSM) to detect a received SBC command in response to a static pattern persisting for a predetermined number of the SBC samples and command decoding logic to decode the received SBC command.

Abstract: Design structures embodied in machine readable medium are provided. Embodiments of the design structure include a memory system comprising: a memory controller; a memory bus terminator; a high speed memory bus that interconnects the memory controller, the memory bus terminator, and at least one memory module; and the at least one memory module, the memory module comprising at least one memory hub device, high speed random access memory served by the memory hub device, two bus signal ports, and a segment of the high speed memory bus fabricated on the memory module so as to interconnect the bus signal ports and the memory hub device, the high speed memory bus connected to the memory hub device by a negligible electrical stub.

Abstract: A memory system for providing a slow command decode over an untrained high-speed interface. The memory system includes a memory system having a memory interface device, an untrained high-speed interface, and a memory controller. The untrained high-speed interface is in communication with the memory interface device. The memory controller generates slow commands and transmits the slow commands to the memory interface device via the untrained high-speed interface. The slow commands operate at a first data rate that is slower than a second data rate utilized by the high-speed interface after it has been trained. The memory interface device receives the slow commands via the untrained high-speed interface, decodes the slow commands, and executes the slow commands.

Abstract: Memory systems are disclosed that include a memory controller; a memory bus terminator; a high speed memory bus that interconnects the memory controller, the memory bus terminator, and at least one memory module, where memory module includes a memory hub device, high speed random access memory served by the memory hub device, two bus signal ports, and a segment of the high speed memory bus fabricated on the memory module so as to interconnect the bus signal ports and the memory hub device, with the high speed memory bus connected to the memory hub device by a negligible electrical stub.

Abstract: A system and method for providing SDRAM mode register shadowing in a memory system. A system includes a memory interface device adapted for use in a memory system. The memory interface device includes an interface to one or more ranks of memory devices, and each memory device includes one or more types of mode registers. The memory interface device also includes an interface to a memory bus for receiving commands from a memory controller. The commands include a mode register set command specifying a new mode register setting for one or more ranks of memory devices and a mode register type. The memory interface device further includes a mode register shadow module to capture settings applied to the mode registers. The module includes a shadow register for each type of mode register and a shadow log for each type of mode register.

Abstract: A memory system including a first memory subsystem having a buffer device with a first port and a second port, one or more memory devices coupled to the buffer device via the second port, and a first two-on-one link for coupling to a memory controller for providing communication between the buffer device and the memory controller. The first two-on-one link is coupled to the first port of the buffer device. The first memory subsystem is configured to transfer data between at least one memory device of the one or more memory devices and the memory controller via the buffer device. The first two-on-one link includes up to two transceivers connected to a single link, with at least one of the up to two transceivers consisting of any one of two or more transmitters for transmitting signals or two or more receivers for receiving signals.

Abstract: A cascaded interconnect system for providing a service interface to a memory system. The cascaded interconnect system includes a master service interface module, a service interface bus, and one or more slave service interface modules. The master service interface module and the slave interface modules are cascade interconnected via the service interface bus. Each slave service interface module is in communication with a corresponding memory module for providing a service to the memory module.

Abstract: Systems and methods for providing a dynamic memory buffer bank policy. Embodiments include a hub device for selecting a bank page policy. The hub device includes an input command stream interface and a bank page policy module. The input command stream interface detects commands from a memory controller that are directed to one or more memory devices that are connected to the hub device. The bank page policy module independently analyzes the commands to determine access patterns to the memory devices and for dynamically selecting between an open bank page policy and a closed bank page policy for the memory devices based on the analysis.

Abstract: Systems and methods for providing dynamic memory pre-fetch. Embodiments include a hub device including an input command stream interface and an adaptive pre-fetch logical unit (APLU). The input command stream interface detects commands from a memory controller directed to one or more memory devices that are connected to the hub device. The APLU independently analyzes the commands to determine access patterns to the memory devices. The APLU also dynamically selects between enabling a pre-fetch function and disabling the pre-fetch function for the memory devices based on the results of the analysis.

Abstract: Systems and methods for providing distributed technology independent memory controllers. Systems include a computer memory system for storing and retrieving data. The system includes a memory bus, a main memory controller, one or more memory devices characterized by memory device protocols and signaling requirements, and one or more memory hub devices. The main memory controller is in communication with the memory bus for generating, receiving, and responding to memory access requests. The hub devices are in communication with the memory bus and with the memory devices for controlling the memory devices responsively to the memory access requests received from the main memory controller and for responding to the main memory controller with state or memory data.

Abstract: A cascaded interconnect system with one or more memory modules, a memory controller and a memory bus that utilizes periodic recalibration. The memory modules and the memory controller are directly interconnected by a packetized multi-transfer interface via the memory bus and provide scrambled data for use in the periodic recalibration.

Abstract: A memory system is provided that supports partial cache line write operations to a memory module to reduce write data traffic on a memory channel. The memory system comprises a memory hub device integrated in the memory module and a set of memory devices coupled to the memory hub device. The memory hub device comprises burst logic integrated in the memory hub device. The burst logic determines an amount of write data to be transmitted to the set of memory devices and generates a burst length field corresponding to the amount of write data. The memory hub also comprises a memory hub controller integrated in the memory hub device. The memory hub controller controls the amount of write data that is transmitted using the burst length field. The memory hub device transmits the amount of write data that is equal to or less than a conventional data burst amount.

Abstract: Systems and methods for providing distributed autonomous power management in a memory system. Embodiments include a memory system for storing and retrieving data for a processing system. The memory system includes a memory controller for receiving and responding to memory access requests, a memory bus in communication with the memory controller, a plurality of memory devices, and a control unit external to the memory controller. The memory devices are in communication with the memory controller via the memory bus, with one or more of the memory devices being associated with a group. The control unit autonomously manages power within and for the group of memory devices.

Abstract: A memory system, data processing system, and method are provided for using cache that is embedded in a memory hub device to replace failed memory cells. A memory module comprises an integrated memory hub device. The memory hub device comprises an integrated memory device data interface that communicates with a set of memory devices coupled to the memory hub device and a cache integrated in the memory hub device. The memory hub device also comprises an integrated memory hub controller that controls the data that is read or written by the memory device data interface to the cache based on a determination whether one or more memory cells within the set of memory devices has failed.

Abstract: A memory system is provided that provides memory system power reduction without reducing overall memory system performance. The memory system comprises a memory hub device integrated in a memory module. The memory hub device comprises a command queue that receives a memory access command from an memory controller via a memory channel at a first operating frequency. The memory system also comprises a memory hub controller integrated in the memory hub device. The memory hub controller reads the memory access command from the command queue at a second operating frequency. By receiving the memory access command at the first operating frequency and reading the memory access command at the second operating frequency an asynchronous boundary is implemented. Using the asynchronous boundary, the memory channel operates at a maximum designed operating bandwidth while the second operating frequency is independently decreased to reduce power being consumed by the set of memory devices.

Abstract: A memory system is provided that reduces latency by running a memory channel fully asynchronous from a memory device frequency. The memory system comprises a memory hub device integrated in a memory module. The memory hub device comprises a command queue that receives a memory access command from an external memory controller via a memory channel at a first operating frequency. The memory system also comprises a memory hub controller integrated in the memory hub device. The memory hub controller reads the memory access command from the command queue at a second operating frequency. By receiving the memory access command at the first operating frequency and reading the memory access command at the second operating frequency an asynchronous boundary is implemented. The first operating frequency is a maximum designed operating frequency of the memory channel and the first operating frequency is independent of the second operating frequency.

Abstract: A memory system is provided that performs error correction at a memory device level. The memory system comprises a memory hub device integrated in the memory module and a link interface integrated in the memory hub device that provides a communication pathway between the memory hub device and an external memory controller. The link interface comprises first error correction logic integrated in the link interface that performs error correction operations on first data that is received from the external memory controller via a first memory channel to be transmitted to a set of memory devices. The first error correction logic generates a first error signal to the external memory controller in response to the first error correction logic detecting a first error in the first data. Link interface control logic integrated in the link interface controls the transmission of the first data to the set of memory devices.