Patent application number | Description | Published |
20090161246 | Random Number Generation Using Hard Disk Drive Information - A hard disk drive enhances random number generation. In particular embodiments, the hard disk drive includes a controller, a hard disk, and a head. The head includes a read sensor for reading patterns on the hard disk. The controller generates a random number based on information associated with the position of the head relative to at least one track of the hard disk. | 06-25-2009 |
20100030958 | Random Number Generation For a Host System Using a Hard Disk Drive - A hard disk drive is provided for enhancing random number generation. In particular embodiments, the hard disk drive includes a storage subsystem and a controller. The controller generates a random number based on information associated with the storage subsystem. The controller transmits the random number to a host system. | 02-04-2010 |
20100205623 | Techniques For Emulating Sequential Device With Constrained Disk Drive - A disk drive apparatus includes at least one disk, a head-arm assembly, and a controller circuit. The head arm assembly includes at least one read/write head. The head-arm assembly is movable to enable the read/write head to access a writable surface of the disk. The controller circuit also causes the read/write head to record data on the writable surface of the disk in a write append format. | 08-12-2010 |
20100232057 | Techniques For Storing Shingle Blocks in a Cache Memory Using a Data Storage Device - A data storage apparatus includes a data storage medium, a write element, a non-volatile cache memory circuit, and a controller circuit. The controller circuit is configured to record data on the data storage medium in groups of overlapping tracks using the write element. The controller circuit is configured to store a shingle block of data from a subset of the overlapping tracks in the non-volatile cache memory circuit, while at least a portion of the data in the shingle block of data is updated. | 09-16-2010 |
20130124943 | Techniques For Storing Data in Stuck Memory Cells - A data storage system includes a memory circuit and a control circuit. The control circuit is operable to receive data bits provided for storage in memory cells of the memory circuit. The control circuit is operable to compare each of the data bits provided for storage in a corresponding one of the memory cells having a stuck-at fault to a value of the stuck-at fault, and to invert each of the data bits having a different value than the value of the stuck-at fault of the corresponding one of the memory cells to generate encoded data bits. The control circuit is operable to generate redundant bits that indicate the encoded data bits to invert to regenerate the data bits. | 05-16-2013 |
20130142024 | Distributed Field Self-test for Shingled Magnetic Recording Drives - A method is described for allowing disk drives, such as shingle-written magnetic recording (SMR) drives, to be shipped for customer use with portions of the magnetic media being left untested. The testing is then completed by the drive self-testing in the field. The drive is made functional at the factory by fully testing at least one operational set of regions including an I-region, an E-region and a write cache region. The operational set of regions works as a separate self-contained virtual disk drive and can be used immediately. The remaining untested areas on the media can be tested in the field by a background task and/or when the first write command is received that requires a new track or operational set of regions (on-the fly testing). | 06-06-2013 |
20140101516 | Encoding and Decoding Data to Accommodate Memory Cells Having Stuck-At Faults - A data storage system includes a memory circuit that has memory cells and a control circuit that is operable to receive data bits provided for storage in the memory cells. The control circuit is operable to receive a first matrix. Each row of the first matrix corresponds to a unique one of the data bits. The control circuit is operable to generate a second matrix having only the rows of the first matrix that correspond to the data bits provided for storage in a subset of the memory cells having stuck-at faults. The control circuit is operable to generate a third matrix having linearly independent columns of the second matrix. The control circuit is operable to encode the data bits to generate encoded data bits and redundant bits using the third matrix. | 04-10-2014 |
20140101517 | Encoding and Decoding Redundant Bits to Accommodate Memory Cells Having Stuck-At Faults - A data storage system has a memory circuit that comprises memory cells and a control circuit that receives data bits provided for storage in the memory cells. The control circuit encodes the data bits to generate a first set of redundant bits and encoded data bits, such that the encoded data bits selected for storage in a first subset of the memory cells with first stuck-at faults have digital values of corresponding ones of the first stuck-at faults. The control circuit encodes the first set of redundant bits to generate a second set of redundant bits. The control circuit performs logic functions on the second set of redundant bits and the encoded data bits to generate a third set of redundant bits, such that redundant bits in the third set of redundant bits selected for storage in a second subset of the memory cells with second stuck-at faults have digital values of corresponding ones of the second stuck-at faults. | 04-10-2014 |
20140156713 | Deadline-Based Scheduling in a Distributed File System - Approaches for retrieving files from a replicated file system. A component receives, from a requestor, a request for a copy of a data unit. The component identifies a plurality of storage nodes that each stores a complete copy of the data unit. The component sends, to the plurality of storage nodes, an instruction to retrieve a copy of the data unit within a specified period of time. At each storage node receiving an instruction, a determination of whether the copy of the data unit may be retrieved within the specified period of time is made, and if so, the copy of the data unit is provided to the component only if the copy of the data unit was actually retrieved within the specified period. The component provides the first copy of the data unit it receives to the requestor and discards any subsequently received copies of the data unit. | 06-05-2014 |
20140164821 | Techniques For Encoding and Decoding Using a Combinatorial Number System - A data storage system includes a memory circuit having memory cells and a control circuit. The control circuit is operable to receive data bits provided for storage in the memory cells. A subset of the memory cells have predetermined stuck-at faults. The control circuit is operable to compute a binomial coefficient for each of the predetermined stuck-at faults based on a bit position of a corresponding one of the predetermined stuck-at faults within the memory cells. The control circuit is operable to add together the binomial coefficients to generate an encoded number using a combinatorial number system. The control circuit is operable to generate a first set of redundant bits that indicate the encoded number. The first set of redundant bits are used to decode bits read from the memory cells to regenerate the data bits. | 06-12-2014 |
20140164873 | Techniques For Storing Bits in Memory Cells Having Stuck-at Faults - A data storage system includes a memory circuit comprising memory cells and a control circuit. The control circuit generates a first set of redundant bits indicating bit positions of the memory cells having stuck-at faults in response to a first write operation if a first rate of the stuck-at faults in the memory cells is greater than a first threshold. The control circuit is operable to encode data bits to generate encoded data bits and a second set of redundant bits that indicate a transformation performed on the data bits to generate the encoded data bits in response to a second write operation if a second rate of stuck-at faults in the memory cells is greater than a second threshold. The encoded data bits stored in the memory cells having the stuck-at faults match digital values of corresponding ones of the stuck-at faults. | 06-12-2014 |
20150082084 | ENHANCED DATA RECOVERY FROM DATA STORAGE DEVICES - Systems, methods, and firmware for recovery of data from storage devices are provided herein. In one example, a data storage device is provided. The data storage device includes a storage portion and a cache portion which caches data intended for storage in the storage portion. Responsive to a recovery read command identifying requested data, the data storage device retrieves stored data corresponding to the requested data from the storage portion without retrieving cached data corresponding to the requested data from the cache portion that supersedes at least a portion of the stored data. Responsive to a cache block list command, the data storage device transfers a list identifying one or more cached blocks of the cached data. Responsive to a read command that identifies at least one cached block, the data storage device retrieves the at least one cached block. | 03-19-2015 |