Abstract: An optimum pathway to data stored on a data storage system having N storage devices and more than N pathways is determined in response to a read request for the data. A sorter separates the read request into an appropriate segment size for sending to the storage devices of the data storage system. An assigner generates the set of read permutations satisfying the read request. A read permutation is selected based on a metric. A collector receives the requested data from the N storage devices in response to the selected read permutation being sent to the storage devices.

Abstract: Desired transformations such as compression, encryption and/or encoding are applied to data such that the number of duplicate chunks in the transformed data is increased and the chunks are predominantly of a predetermined size. Additionally, the unique and duplicate chunks of transformed data are identified. A variable-sized window is passed over the set of data to generate a working chunk of transformed data that is of the predetermined size. When the working chunk is a duplicate chunk of data, a next group of untransformed data is selected from the set of data, transformed and then evaluated. When the working chunk is not a duplicate chunk of data, a next group of data is selected by sliding the window over the set of data to generate another working chunk that is evaluated.

Abstract: A three-dimensional solid-state memory is formed from a plurality of bit lines, a plurality of layers, a plurality of tree structures and a plurality of plate lines. Bit lines extend in a first direction in a first plane. Each layer includes an array of memory cells, such as ferroelectric or hysteretic-resistor memory cells. Each tree structure corresponds to a bit line, has a trunk portion and at least one branch portion. The trunk portion of each tree structure extends from a corresponding bit line, and each tree structure corresponds to a plurality of layers. Each branch portion corresponds to at least one layer and extends from the trunk portion of a tree structure. Plate lines correspond to at least one layer and overlap the branch portion of each tree structure in at least one row of tree structures at a plurality of intersection regions.

Abstract: Error tolerance is increased for a storage system having a plurality of arrays by making local redundancy in a selected array globally available throughout the storage system. To achieve the increased error tolerance, a donor array is selected from the plurality of arrays when the difference between a minimum Hamming distance of the donor array and a minimum Hamming distance of a recipient array is greater or equal to 2. A donor storage unit is selected in the donor array and recipient information is then rebuilt from the recipient array on the selected storage unit. The selected storage unit is indicated to the donor array as having been donated before the lost information is rebuilt on the selected storage unit. Preferably, the minimum Hamming distance of the recipient array is d?2 before the donor array is selected from the plurality of arrays.

Abstract: A magnetic tunnel element that can be used, for example, as part of a read head or a magnetic memory cell, includes a first layer formed from an amorphous material, an amorphous tunnel barrier layer, and an interface layer between the first layer and the tunnel barrier layer. The interface layer is formed from a material that is crystalline when the material is in isolation from both the first layer and the tunnel barrier layer. Alternatively, the thickness of the interface layer is selected so that the interface layer is not crystalline. The first layer is formed from at least one material selected from the group consisting of amorphous ferromagnetic material, amorphous ferromagnetic materials, and amorphous non-magnetic materials. The interface layer is formed from a material selected from the group consisting of a ferromagnetic material and a ferrimagnetic material.

Abstract: A file system for streaming media uses at least one set of a plurality of storage bands that are arranged sequentially on a magnetic storage disk. Each storage band contains a plurality of storage blocks. At least one data file that is formed from a plurality of sequential data blocks and contains, for example, media content and/or video data is stored in a set of storage bands so that each data block of the data file is stored in a sequential manner with respect to consecutively sequential data blocks. The plurality of storage blocks contained in each storage band are sequentially arranged in the storage band and the storage blocks contained in each storage band sequentially store data blocks of the data file.

Abstract: A data storage subsystem that includes three data storage units, three check storage units, and an array controller coupled to the three data and three check storage units can tolerate failure of any three data and check storage units failures can be occur before data stored on the data storage subsystem is lost. Information is stored on the data storage subsystem as a symmetric Maximum Distance Separation code, such as a Winograd code, a Reed Solomon code, an EVENODD code or a derivative of an EVENODD code. The array controller determines the contents of the check storage units so that any three erasures of the data storage units and the check storage units can be corrected by the array controller. The array controller updates a block of data contained in any one of the data storage units and the check storage units using only six IO operations.

Abstract: A client node of a distributed storage system adaptive determines on an operation-by-operation basis whether to process a network-RAID IO operation (IO request) locally at the client node or to forward the IO request to a storage server of the system for processing. The client node determines to process the requested network-RAID operation at the client node when a local estimator for a type of the requested network-RAID operation is less than a central estimator for the type of the requested network-RAID operation. Otherwise, the client node determines to process the requested network-RAID operation at a storage server when the local estimator for the type of the requested network-RAID operation is greater than the central estimator for the type of the requested network-RAID operation.

Abstract: A micro-fabricated chip having a stationary structure and a movable structure with a gimbal structure allows pitch and roll motion of the movable structure with respect to the stationary structure. One embodiment of the gimbal structure includes a dimple surface making a rolling-type contact with the stationary structure, and a center bar and a plurality of bar members. An alternative embodiment of the gimbal structure includes a plurality of torsion bar members. Another alternative embodiment of the gimbal structure includes a plurality of flexible members. The micro-fabricated chip can be a passive chip structure or, alternatively, a microactuator having a movable structure that moves in a rotational direction or a translational direction with respect to the stationary structure.

Abstract: A physical read ahead is implemented at the filing system level by using a two-level page cache. When a request is received for a page of data within a file, such that the file has a corresponding inode number, a page cache is searched for the requested page of data based on the corresponding inode number and a page number corresponding to the requested page of data. The request is translated into an actual location on the storage device when the page of data is not found in the page cache, and a search of the page cache is performed using an inode representing the storage device. A handle identifying the page of data in the page cache is updated to logically associate the page with a user file inode. Least recently used physical read-ahead data is evicted from the page cache.

Abstract: A technique for setting the initial servo track pitch for a servo system of a hard disk drive (HDD) is based on using a secondary actuator, such as a microactuator or a milliactuator. The actuator of the HDD is positioned against a crash stop and a burst pattern is written on a hard disk while the read/write head is in a first position. A bias voltage of the secondary actuator is incrementally changed to change the position of the read/write head and a burst pattern is written for each change. The overlap is determined as a sum of the averaged amplitudes of the burst patterns that are adjacent to a selected burst pattern divided by the averaged amplitude of the selected burst pattern. The process is terminated when the determined overlap for each selected burst pattern is within a selected criterion of a target overlap value.

Abstract: The Hamming distance of an array of storage devices is increased by generating a parity check matrix based on column equations that are formed using an orthogonal parity code and includes a higher-order multiplier that changes each column. The higher order multiplier is selected to generate a finite basic field of a predetermined number of elements. The array has M rows and N columns, such that M is greater than or equal to three and N is greater than or equal to three. Row 1 through row M?2 of the array each have n–p data storage devices and p parity storage devices. Row M?1 of the array has n?(p+1) data storage devices and (p+1) parity storage devices. Lastly, row M of the array has N parity storage devices.

Abstract: A hard disk drive (HDD) uses a technique for setting the initial servo track pitch for a servo system by using a secondary actuator, such as a microactuator or a milliactuator. The actuator of the HDD is positioned against a crash stop and a burst pattern is written on a hard disk while the read/write head is in a first position. A bias voltage of the secondary actuator is incrementally changed to change the position of the read/write head and a burst pattern is written for each change. The overlap is determined as a sum of the averaged amplitudes of the burst patterns that are adjacent to a selected burst pattern divided by the averaged amplitude of the selected burst pattern. The process is terminated when the determined overlap for each selected burst pattern is within a selected criterion of a target overlap value.

Abstract: Channel parameters for a magnetic readback channel are optimized by detecting a readback signal that is recorded on a magnetic medium. The readback signal contains a plurality of predetermined-length control fields. Each control field is arranged between two user data fields and contains at least one transition. At least one selected readback parameter, such as a frequency of a readback channel system clock, a gain of the readback channel, a equalization response of the readback signal, and/or an amplitude asymmetry of the readback channel, is optimized based on information contained in at least one control field.

Abstract: A RAID-configured grouped-object storage system provides reduced storage space overhead for small objects. The storage system includes a plurality stripes arranged across a plurality of physical objects. Each stripe includes a plurality of storage blocks that are each mapped on to a respectively different physical object. The storage system also includes a plurality of virtual objects each containing at least one storage block. A group of virtual objects is formed when a virtual object contains less storage blocks than the number of stripes by associating the virtual object with at least one virtual object containing less storage blocks than the number of stripes and/or at least one storage block containing zero values so that the storage blocks of each group of virtual objects equals the number of stripes. The storage blocks of each virtual object and of each group of virtual objects are mapped to a respectively different stripe.

Abstract: A read head for use with an interconnect transmission line having a characteristic impedance of Z0 includes a tunnel valve device and a shunt resistor RS that is connected in parallel across the tunnel valve device. The tunnel valve device has a device resistance RT corresponding to a predetermined resistance-area (RA) product. The value of the shunt resistance is based on the parallel combination of RT and RS substantially equaling the characteristic impedance Z0 of the interconnect transmission line. The predetermined resistance-area (RA) product is about equal to at least about 10 Ohms-?m2. Alternatively, the predetermined resistance-area (RA) product is about equal to a “corner” value of RAc for the tunnel valve device.