A decoding apparatus includes a differential decoder, an error correction decoder and a controller. The differential decoder performs differential decoding according to a differential encoding dependency to generate a differential decoding result. The error correction decoder performs a decoding process on multiple packets that need to be corrected according to the differential decoding result to accordingly generate respective error correction records, wherein the packets are generated according to the differential decoding results, and the packets include a first packet and a second packet. When the error correction record of the first packet indicates that the decoding process of the first packet is unsuccessful, the controller generates a set of error position information according to the error correction record of the second packet, and requests the error correction decoder to perform another decoding process on the first packet according to the error position information.

Compact timestamps and related methods, systems and devices are described. An encoder is configured to generate compact timestamps of the disclosure by sampling states of linear feedback shift registers (LFSRs). A decoder may be configured to determine timing information responsive to the compact timestamps.

A method for data communication between a first node and a second node over a data path includes determining one or more redundancy messages from data messages at the first node using an error correcting code and transmitting messages from the first node to the second node. The transmitted messages include the data messages and the redundancy messages. The method includes, receiving, at the first node, a first plurality of messages including messages indicative of a rate of arrival at the second node of the messages transmitted from the first node and messages indicative of successful and unsuccessful delivery of the messages transmitted from the first node to the second node. A first transmission limit and a second transmission limit are maintained according to the first plurality of messages. Transmission of messages from the first node to the second node is limited according to the maintained first transmission limit, and according to the second transmission limit.

Methods and apparatus are provided for controlling wireless signal transmissions, wherein problematic symbol patterns are relocated to an erasure region of a data packet prior to erasure encoding and transmission. Relocating the problematic symbol patterns is done so that, when the resulting erasure codeword is punctured and transmitted, the problematic patterns are not transmitted. Yet, those patterns can be restored by the decoder at the receiving device using an erasure decoder in accordance with erasure decoding techniques, e.g., punctured low-density parity-check (LDPC) decoding techniques. In this manner, problematic symbol patterns that may be corrupting during transmission due to noise are removed (punctured) prior to transmission, then restored by the decoder during decoding.

Systems and methods are disclosed for processing data. In one exemplary implementation, there is provided a method of generating H output data from W data input streams produced from input data. Moreover, the method may include generating the H discrete output data components via application of the W data inputs to one or more transforming components or processes having specified mathematic operations and/or a generator matrix functionality, wherein the W data inputs are recoverable via a recovery process capable of reproducing the W data inputs from a subset (any W members) of the H output data streams. Further exemplary implementations may comprise a transformation process that includes producing an H-sized intermediary for each of the W inputs, combining the H-sized intermediaries into an H-sized result, and processing the H-sized result into the H output data structures, groups or streams.

Example apparatus and methods produce a set of rateless erasure codes (e.g., fountain codes) for a file stored in a primary data store (e.g., hard drive) or in an archive system. The archive system may store the file in a redundant array of independent disks (RAID). A first subset of the rateless erasure codes are stored in an object storage using a synchronous protocol. A second subset of rateless erasure codes are stored in the object storage using an asynchronous protocol. The object storage system may inform the archive system when desired redundancy has been achieved or when desired redundancy has been lost. The archive system may buffer rateless erasure codes before providing the codes to the object storage to improve performance. A failure in the archive system or object storage system may be mitigated by retaining the file in the primary data store until the desired redundancy is achieved.

Apparatuses, methods and storage medium associated with generating erasure codes for data to be stored in a storage system. In embodiments, a method may include launching, by storage system, a plurality of instances of an erasure code generation module, based at least in part on hardware configuration of the storage system. Additionally, the method may further include setting, by the storage system, operational parameters of the plurality of instances of the erasure code generation module, based at least in part on current system load of the storage system. Further, the method may include operating, by the storage system, the plurality of instances of the erasure code generation module to generate erasure codes for data to be stored in the storage system, in accordance with the operational parameters set. Other embodiments may be described and claimed.

Techniques described and suggested herein include systems and methods for minimizing inter-facility data transfer during retrieval of data archives stored on data storage systems using redundancy coding techniques. For example, redundancy coded shards, which may include identity shards that contain unencoded original data of archives, may be configured such that a variable number of the shards can be leveraged to meet performance requirements or time-to-retrieval limitations for retrieval requests associated with the archives stored and/or encoded therein. Under some circumstances, implementing systems may monitor throughput rates, capabilities, and burdens, so as to preferentially retrieve data such that the identity shards are favored and fewer hosting data storage facilities are used for a given retrieval.

A dispersed storage network facilitates isolating the introduction of software defects in dispersed storage units. A search strategy is employed whereby after identifying a test failure in a current version of the memory software code, a code version since a previous successfully tested version is identified. An interim version that represents the point at which approximately one half the changes were introduced is then tested. When there is a test failure, the next interim version selected for testing represents the point at which approximately one half the changes were introduced between the first interim version tested and the current version. If no failure, a next interim version is tested that represents the point at which approximately one half the changes were introduced between the previous successfully tested version and the first interim version tested.

A method includes determining, by a managing unit of a dispersed storage network (DSN), an addition of a new storage unit to a group of storage units. The DSN includes a logical address space divided into a set of logical address sub-spaces, one of which is allocated to the group of storage units. The method further includes reorganizing, by the managing unit, distribution of the logical address sub-space among the new storage unit and each storage unit in the group of storage units to produce a reorganized logical address sub-space. The allocation includes the new storage unit's portion being between portions of first and second storage units. The method further includes transferring, by the first storage unit, a first group of encoded data slices to the new storage unit and transferring, by the second storage unit, a second group of encoded data slices to the new storage unit.