Abstract: A memory system is described, where a plurality of memory modules is connected to a memory controller. Erase operations of the memory modules are coordinated by the memory controller such that, when data is stored in a group of memory modules configured to be a RAID (Redundant Array of Independent “Disks”) group, erase or refresh operations performed on the memory modules of the RAID group are synchronized, scheduled, or controlled to reduce the latency in reading the data stored on the RAID modules.

Abstract: Non-volatile memory systems such as those using NAND FLASH technology have a property that a memory location can be written to only once prior to being erased, and a contiguous group of memory locations need to be erased simultaneously. The process of recovering space that is no longer being used for storage of current data, called garbage collection, may interfere with the rapid access to data in other memory locations of the memory system during the erase period. The effects of garbage collection on system performance may be mitigated by performing portions of the process contemporaneously with the user initiated reading and writing operations. The memory circuits and the data may also be configured such that the data is stored in stripes of a RAID array and the scheduling of the erase operations may be arranged so that the erase operations for garbage collection are hidden from the user operations.

Abstract: A memory system and method of operating the same is described, where the memory system is used to store data in a RAIDed manner. The stored data may be retrieved, including the parity data so that the stored data is recovered when the first of either the stored data without the parity data, or the stored data from all but one memory module and the parity data, has been received. The writing of data, for low write data loads, is managed such that only one of the memory modules of a RAID stripe is being written to, or erased, during a time interval.

Abstract: Efficient processing of user data read requests in a deduplicated data storage system places the metadata for most frequently requested data in data structures and locations in the system hierarchy where the metadata will be most rapidly available. The total amount of such metadata makes storing all of the metadata in high speed memory expensive, and the system and method described uses both the temporal and the spatial characteristics of the user system activity in any epoch to adjust the contents of metadata cache so as to respond to the dynamics of a multi user or multi-application environment where the storage system is not made aware of the time changing mix of operations except by observation of the individual requests. A history record is used to promote metadata from the slow memory to the fast memory, and a process selection may be adjusted based on the address-space activity.

Abstract: Maintenance of reliable and highly available electronic systems to perform servicing and preventive maintenance may need to be performed without interruption of operations. Removal of circuit cards from a chassis may render the connectors on a chassis vulnerable to inadvertent short circuiting of power sources by stray metallic objects. A configuration where the power is removed from a connector as the circuit card is being extracted eliminates his possibility. The control circuits for the power supply connections and the power supplies are themselves redundant so that they may be similarly serviced.

Abstract: A power supply and circuit module includes a housing, a power supply and a circuit module received in the housing. The power supply and the circuit module can be removably installed into and removed from a cage of an electronic system as a unit by a sliding action. The cage includes a first bottom plate, a backplane connected to the first bottom plate. A plurality of standoffs are formed on the first bottom plate for supporting a motherboard thereon. An electrical connector, such as a card connector, is directly formed on the backplane for connecting a circuit card.

Abstract: Efficient processing of user data read requests in a deduplicated data storage system places the metadata for most frequently requested data in data structures and locations in the system hierarchy where the metadata will be most rapidly available. The total amount of such metadata makes storing all of the metadata in high speed memory expensive, and the system and method described uses both the temporal and the spatial characteristics of the user system activity in any epoch to adjust the contents of metadata cache so as to respond to the dynamics of a multi user or multi-application environment where the storage system is not made aware of the time changing mix of operations except by observation of the individual requests. A history record is used to promote metadata from the slow memory to the fast memory, and a process selection may be adjusted based on the address-space activity.

Abstract: A system and method for storing compressed data in a memory system includes identifying user data to be compressed and compressing pages of user data to form data extents that are less than or equal to the uncompressed data. A plurality of compressed pages are combined to a least fill a page of the memory. The data may be stored as sectors of a page, where each sector includes a CRC or error correcting code for the compressed data of that sector. The stored data may also include error correcting code data for the uncompressed page and error correcting code for the compressed page. When data is read in response to a user request, the sector data is validated using the CRC prior to selecting the data from the read sectors for decompression, and the error correcting code for the uncompressed page may be used to validate the decompressed data.

Abstract: A system and method for storage of data is described where the data and commands received by a storage system is processed using at least a pair of redundant channels, configured so that received data buffered in a first channel is also buffered by a second channel prior to acknowledgement of the completion of the command execution. This permits a low latency of response to commands while securely storing the data. Data that is buffered in the first channel may be processed for storage, or for deduplication or compression prior to sending to the storage system subsequent to the acknowledgement of completion of the command and the data may then be purged from the data buffers in the redundant channels. A file identified as being smaller in size than the size allocated to associated metadata may be stored as part of the metadata without being sent to the storage system.