Abstract:
A data memory system is described, where there may be an asymmetry in the time needed to write or erase data and the time needed to read data. The data may be stored using a RAID data storage arrangement and the reading, writing and erasing operations on the modules arranged such that the erasing and writing operations may be performed without significant latency for performing a read operation. Where a failure of a memory module in the memory system occurs, methods for recovering the data of the failed module are disclosed which may selected in accordance with policies that may relate to the minimizing the possibility of irretrievable data loss, or degradation of latency performance.
Abstract:
A memory system is described, where a plurality of memory modules is connected to a memory controller. The power status of each of the memory modules is controlled, depending on the functions being performed by the memory module. When no read or write operation is being performed on a particular memory module, at least a portion of the circuitry may be operated in a lower power mode. A memory circuit associated with the memory module may be placed in a low power mode by disabling a clock. The memory circuit data integrity may be secured by issuing refresh commands while when the memory circuit is in the lower power mode, by enabling the clock, issuing the refresh command, and disabling the clock after completion of the refresh operation.
Abstract:
A storage access system provides consistent memory access times for storage media with inconsistent access latency and reduces bottlenecks caused by the variable time delays during memory write operations. Data is written iteratively into multiple different media devices to prevent write operations from blocking all other memory access operations. The multiple copies of the same data then allow subsequent read operations to avoid the media devices currently servicing the write operations. Write operations can be aggregated together to improve the overall write performance to a storage media. A performance index determines how many media devices store the same data. The number of possible concurrent reads varies according to the number of media devices storing the data. Therefore, the performance index provides different selectable Quality of Service (QoS) for data in the storage media.
Abstract:
A storage proxy monitors storage access operations. Different address alignments are identified between the storage access operations and data blocks in a storage media. A dominant one of the address alignments is identified. Data blocks are mapped into the storage media to remove the dominant address alignment. An array of counters can be used to track the address alignments for different storage access sizes and the address alignment associated with the highest number of storage access operations is used as the dominant address alignment.
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 memory system having a plurality of modules operated so that a group of memory modules may operation in a RAID configuration having an erase hiding property. The RAID groups are mapped to areas of memory in each of the memory modules of the RAID group. More than one RAID group may be mapped to a memory module and the erase operations of the RAID groups coordinated such that the erase operations do not overlap. This may improve the utilization of a bus over which the memory module communicates with the controller. Where a memory module is replaced by a memory module having an increased storage capacity, the additional storage capacity may be mapped to an expanded logical address space.
Abstract:
A multi-tiered cache manager and methods for managing multi-tiered cache are described. Multi-tiered cache manager causes cached data to be initially stored in the RAM elements and selects portions of the cached data stored in the RAM elements to be moved to the flash elements. Each flash element is organized as a plurality of write blocks having a block size and wherein a predefined maximum number of writes is permitted to each write block. The portions of the cached data may be selected based on a maximum write rate calculated from the maximum number of writes allowed for the flash device and a specified lifetime of the cache system.
Abstract:
A memory system is described, where the transmission time of data between memory modules is managed so that the overall time delay between specified points in the memory system is maintained a constant. Each lane of a multilane bus may be separately managed, and a data frame evaluated at the destination module, without a need for deskewing at intermediate modules. The time delay in propagation of the data through a module, which may have a switch to route the data, is reduced by operating the data path through the module at one or more submultiples of the bus serial data rate, and selecting the sampling point of the received data so that variations in time delay due to temperature changes or ageing are accommodated.
Abstract:
A flash memory management method and apparatus provides for the separation of the command and data paths so that communication paths may be used more efficiently. A unique sequence identifier is assigned to a write command and the associated data and association of the data and commands are validated prior to writing to the memory by comparing the unique sequence numbers of the data and command prior to executing the command. This comparison is performed after the data and command have traversed the communication paths.
Abstract:
A method and system for managing a flash memory system facilitates the use of TRIM or similar operations so as to release physical memory space of logical block addresses that are declared to be deleted by a user file management system. A series of data structures accounts for the levels of indirection used to manage the correspondence between a user logical block address and the physical location of the data in the memory system and to respond to user read and write requests by efficiently determining the current status of the user logical block address in the frame of reference of the memory system and substantially decoupling the TRIM management from the garbage collection and wear leveling operations.