Abstract: The control logic for a hot-pluggable memory cartridge for use in a redundant memory system. To implement a hot-pluggable memory cartridge in a redundant memory system, control logic to control the sequence of events for powering-up and powering-down a memory cartridge is provided.

Abstract: A processor-based device having a plurality of memory cartridges secured within a chassis by a lever system. The processor-based device comprises an indication system to indicate memory system operating conditions. Each memory cartridge has a protective assembly to protect memory elements within the memory cartridge when the memory cartridge is removed from the processor-based device. The processor-based device is operable such that at least one memory cartridge may be removed from the processor-based device without affecting operation of the processor-based device.

Abstract: Methods for improving processor performance. Specifically, by reducing some of the latency cycles within a host controller, request processing speed can be improved. One technique for improving processing speed involves initiating a deferred reply transaction before the data is available from a memory controller. A second technique involves anticipating the need to transition from a block next request (BNR) state to a bus priority request (BPRI) state, thereby eliminating the need to wait for a request check to determine if the BPRI state must be implemented.

Abstract: A technique for resynchronizing a memory system. More specifically, a technique for resynchronizing a plurality of memory segments in a redundant memory system after a hot-plug event. After a memory cartridge is hot-plugged into a system, the memory cartridge is synchronized with the operational memory cartridges such that the memory system can operate in lock step. A refresh counter in each memory cartridge is disabled to, generate a first refresh request to the corresponding memory segments in the memory cartridge. After waiting a period of time to insure that regardless of what state each memory cartridge is in when the first refresh request is initiated all cycles have been completely executed, each refresh counter is re-enabled, thereby generating a second refresh request. The generation of the second refresh request to each of the memory segments provides synchronous operation of each of the memory cartridges.

Abstract: A mechanism for executing requests in a system. More specifically, a technique for processing requests to a memory system is provided. A shift register may be used to store an index associated with requests, such as read and write requests, to a memory system. Each request is stored in a respective queue depending on the source of the request and the request type (e.g. read or write). Each request includes flags which may be set to determine the processing order of the requests, such that out-of-order processing is feasible. An index corresponding to each of the requests is stored in an index shifter to facilitate the out-of-order processing of the requests. Alternatively, a shift register may be used to store each of the requests. Rather than shifting the indices to facilitate the out-of-order processing of requests, depending on the state of the corresponding request flags, the entire entry may be shifted.

Abstract: The specification discloses a method and related system that allows hardware devices to participate in the coherency domain of a computer system. More particularly, hardware devices such as network interface cards, audio cards, input/output cards, and the like, are allowed to participate on at least a limited basis in the coherency domain by having cache memory that duplicates a FIFO buffer in main memory used to exchange information between software and the hardware. To exchange information, software writes to the FIFO buffer which invalidates the data in the cache-type memory of the hardware device, and the invalidation message acts to notify the hardware device of the availability of information in the FIFO buffer.

Abstract: A method of adding memory capacity to a computer system. The computer system comprises a redundant memory system including a plurality of memory cartridges. By powering-down a memory cartridge, adding an additional memory module to the memory cartridge, and powering-up the memory cartridge for each memory cartridge in the system, the system can transition from a redundant mode of operation to a non-redundant mode of operation for each power-down, thus allowing the computer system to remain functional during the addition of the memory module. Alternatively, memory cartridges with higher memory capacity than those currently present in the computer system can be used to replace existing memory cartridges in the computer system, using the same techniques.

Abstract: A system and technique for correcting data errors in a memory device. More specifically, data errors in a memory device are corrected by scrubbing the corrupted memory device. Generally, a host controller delivers a READ command to a memory controller. The memory controller receives the request and retrieves the data from a memory sub-system. The data is delivered to the host controller. If an error is detected, a scrub command is induced through the memory controller to rewrite the corrected data through the memory sub-system. Once a scrub command is induced, an arbiter schedules the scrub in the queue. Because a significant amount of time can occur before initial read in the scrub write back to the memory, an additional controller may be used to compare all subsequent READ and WRITE commands to those scrubs scheduled in the queue.

Abstract: A technique for selecting events associated with a hot-plug operation. More specifically, a programmable configuration register may be used to provide a mechanism for periodically scheduling requests associated with a hot-plug operation, such as initialization, rebuild, and verify requests. An arbiter is provided to facilitate an ordered access to a memory system. A user can select a periodic interval such that hot-plug requests are periodically executed during the execution of normal requests through the arbiter. The user-selectable interval may be dependent on the specific application of the system and the importance of operating in a redundant mode.

Abstract: A computer system includes a plurality of memory modules that contain semiconductor memory, such as DIMMs. The system includes a host/data controller that utilizes an XOR engine to store data and parity information in a striped fashion on the plurality of memory modules to create a redundant array of industry standard DIMMs (RAID). The system supports DIMMs having X4 and X8 configurations. The system also transitions between various states, including a redundant state and a non-redundant state, to facilitate “hot-plug” capabilities utilizing its removable memory cartridges.

Abstract: A computer system includes a plurality of memory modules that contain semiconductor memory, such as DIMMs. The system includes a host/data controller that utilizes an XOR engine to store data and parity information in a striped fashion on the plurality of memory modules to create a redundant array of industry standard DIMMs (RAID). The host/data controller also interleaves data on a plurality of channels associated with each of the plurality of memory modules.

Abstract: Method and apparatus for improving processor performance. In some embodiments, processing speed may be improved by reusing data stored in a buffer during an initial request by subsequent requests. Assignment of temporary storage buffers in a controller may be made to allow for the potential for reuse of the data. Further, a hot buffer may be designated to allow for reuse of the data stored in the hot buffer. On subsequent requests, data stored in the hot buffer may be sent to a requesting device without re-retrieving the data from memory.

Abstract: A method of replacing a memory module in a computer system. Specifically, a method for replacing a memory module in a segment of a redundant memory system, without powering-down the memory system.

Abstract: A height adjustable pedestal having two or more height adjustable telescoping columns can be raised or lowered freely without binding. The telescoping columns engage a furniture component through at least two pivots and at least one slider. Pivotal and sliding engagement of the furniture component with the telescoping columns allows the furniture component to slide and pivot freely over the column precluding axial misalignment of the telescoping members of the columns due to non-parallelity between columns, or misalignment caused by columns moving at disparate speeds. Engagement of the furniture component in this manner also allows the telescoping columns to be adjusted independently of one another providing, for example, a tiltable table top or chair seat. Further, the table top or chair seat can slide in relationship to the height adjustable telescoping columns.

Abstract: A processor-based device having a plurality of memory cartridges secured within a chassis by a lever system. The processor-based device comprises an indication system to indicate memory system operating conditions. Each memory cartridge has a protective assembly to protect memory elements within the memory cartridge when the memory cartridge is removed from the processor-based device. The processor-based device is operable such that at least one memory cartridge may be removed from the processor-based device without affecting operation of the processor-based device.

Abstract: A technique for resynchronizing a memory system. More specifically, a technique for resynchronizing a plurality of memory segments in a redundant memory system after a hot-plug event. After a memory cartridge is hot-plugged into a system, the memory cartridge is synchronized with the operational memory cartridges such that the memory system can operate in lock step. A refresh counter in each memory cartridge is disabled to, generate a first refresh request to the corresponding memory segments in the memory cartridge. After waiting a period of time to insure that regardless of what state each memory cartridge is in when the first refresh request is initiated all cycles have been completely executed, each refresh counter is re-enabled, thereby generating a second refresh request. The generation of the second refresh request to each of the memory segments provides synchronous operation of each of the memory cartridges.

Abstract: A system and technique for detecting data errors in a memory device. More specifically, data errors in a memory device are detected by initiating an internal READ command or verify operation from a set of logic which is internal to the memory system in which the memory devices reside. Rather than relying on a READ command to be issued from an external device, via a host controller, the verify logic initiates verify routine in response to an event such as an operator instruction, hot-plug operation, or a periodic schedule. By implementing the verify operation, the system does not rely on external READ commands to verify data integrity. The verify routine may rely on typical ECC error logging mechanisms and may be used in a RAID memory architecture. Further, the verify routine may be used in conjunction with other error logging and correction logic, as well as scrubbing logic.

Abstract: A technique for resynchronizing a memory system. More specifically, a technique for resynchronizing a plurality of memory segments in a redundant memory system after a hot-plug event. After a memory cartridge is hot-plugged into a system, the memory cartridge is synchronized with the operational memory cartridges such that the memory system can operate in lock step. A refresh counter in each memory cartridge is disabled to generate a first refresh request to the corresponding memory segments in the memory cartridge. After waiting a period of time to insure that regardless of what state each memory cartridge is in when the first refresh request is initiated all cycles have been completely executed, each refresh counter is re-enabled, thereby generating a second refresh request. The generation of the second refresh request to each of the memory segments provides synchronous operation of each of the memory cartridges.

Abstract: A processor-based device having a plurality of memory cartridges secured within a chassis by a lever system. The processor-based device comprises an indication system to indicate memory system operating conditions. Each memory cartridge has a protective assembly to protect memory elements within the memory cartridge when the memory cartridge is removed from the processor-based device. The processor-based device is operable such that at least one memory cartridge may be removed from the processor-based device without affecting operation of the processor-based device.

Abstract: The control logic for a hot-pluggable memory cartridge for use in a redundant memory system. To implement a hot-pluggable memory cartridge in a redundant memory system, control logic to control the sequence of events for powering-up and powering-down a memory cartridge is provided.