A method is provided for encoding a stream of source packets, in which a plurality of k source packets are packet-level forward error correction encoded to form a plurality of n-k error-correcting wildcard packets, wherein the k source packets and n-k wildcard packets are to be transmitted to a receiver. After the arrival of each source packet, for each byte of the source packet, the respective error correction contributions to the corresponding bytes of the plurality of wildcard packets are computed. The source packet is transmitted to the receiver without waiting for the arrival of another source packet of the plurality of source packets. For each wildcard packet byte, the error correction contribution of the source packet is summed in an accumulator. After the error correction contributions have been computed using all k source packets and summed for all n-k wildcard packets, the wildcard packets are transmitted to the receiver.

Method for packet-level fec encoding, in which on a source packet-by-source packet basis, the error correction contributions of a source packet to a plurality of wildcard packets are computed, and the source packet is transmitted thereafter

The present invention relates to a system for (1) protecting the transmission of packet streams between a host computer and one or more client computers, and (2) upon reception, (a) reconstructing any outage damage caused during the transmission to the packet streams, and (b) digitally recording the reconstructed packet streams to a file. The present invention also relates to a method for dynamically generating a file index table as the packet stream is being digitally recorded.

System for protecting the transmission of live data streams, and upon reception, for reconstructing the live data streams and recording them into files

Briefly, the present invention relates to an information dispersal sytem in which original data to be stored is separated into a number of data 'slices' in such a manner that the data in each subset is less usable or less recognizable or completely unusable or completely unrecognizable by itself except when combined with some or all of the other data subsets. These data subsets are stored on separate storage devices as a way of increasing privacy and security. In accordance with an important aspect of the invention, a metadata management system stores and indexes user files across all of the storage nodes. A number of applications run on the servers supporting these storage nodes and are responsible for controlling the metadata. Metadata is the information about the data, the data slices or data subsets and the way in which these data subsets are dispersed among different storage nodes running over the network. As used herein, metadata includes data source names, their size, last modification date, authentication information etc. This information is required to keep track of dispersed data subsets among all the nodes in the system. Every time new data subsets are stored and old ones are removed from the storage nodes, the metadata is updated. In accordance with an important aspect of the invention, the metadata management system stores metadata for dispersed data where: the dispersed data is in several pieces; the metadata is in a separate dataspace from the dispersed data. Accordingly, the metadata management system is able to manage the metadata in a manner that is computationally efficient relative to known systems in order to enable broad use of the invention using the types of computers generally used by businesses, consumers and other organizations currently.

Metadata management system for an information dispersed storage system

An improved system for accessing data within a distributed data storage network (“DDSN”) is disclosed. In a system implementing the disclosed invention, traffic is routed to individual slice servers within the DDSN in accordance with objective criteria as well as user-defined policies. In accordance with one aspect of the disclosed invention, when a data segment is written to a DDSN, the segment is divided into multiple data slices, which are simultaneously transmitted to different slice servers. In accordance with another aspect of the disclosed invention, when a data segment is read from a DDSN, a list of slice servers, each containing a data slice that could be used to reconstruct the requested data segment, is assembled, and sorted in accordance with a preference rating assigned to each of the slice servers. Sufficient data slices to reconstruct the data segment are then read in accordance with the preference ranking of the slice servers.

Smart access to a dispersed data storage network

A digital data file storage system is disclosed in which original data files to be stored are dispersed using some form of information dispersal algorithm into a number of file “slices” or subsets in such a manner that the data in each file share is less usable or less recognizable or completely unusable or completely unrecognizable by itself except when combined with some or all of the other file shares. These file shares are stored on separate digital data storage devices as a way of increasing privacy and security. As dispersed file shares are being transferred to or stored on a grid of distributed storage locations, various grid resources may become non-operational or may operate below at a less than optimal level. When dispersed file shares are being written to a dispersed storage grid which not available, the grid clients designates the dispersed data shares that could not be written at that time on a Rebuild List. In addition when grid resources already storing dispersed data become non-available, a process within the dispersed storage grid designates the dispersed data shares that need to be recreated on the Rebuild List. At other points in time a separate process reads the set of Rebuild Lists used to create the corresponding dispersed data and stores that data on available grid resources.

System for rebuilding dispersed data

A method and system are provided for transferring data from a host computer to one or more subscriber computers, the data consisting of k original packets. The method includes the steps of encoding the k original packets to form n encoded packets, where n>k, transmitting the encoded packets from the host computer to the subscriber computers, receiving some of the transmitted packets, and decoding any combination of k correctly-received encoded packets to reconstruct the k original packets.

Method and system for error-free data transfer

A system and method for transmitting information between a host computer and one or more subscriber computers via a satellite is provided. One or more live streams of data representing the information are inputted in the host computer. The respective pacing factors are measured from the live data streams. The respective virtual files are created from the live data streams. The virtual files are packet-encoded to generate respective streams of encoded packets. The streams of encoded packets and pacing factors are transmitted to the subscriber computers via satellite.

Method and system for reliable broadcasting of data files and streams

We consider problems of decision making based on imperfect information. We derive Bayesian optimal decision procedures for some simple one-person games on trees in which the player is given redundant but noisy information about the true configuration of the game. Our procedures are computationally efficient, and the decision rules which they implement are describable by simple formulas. Not surprisingly, the presence of noise greatly affects the decision procedure, and decisions procedures that are optimal for the corresponding noiseless games may be far from optimal in the presence of noise. In many cases, the optimal decision depends not only on the given noisy data but also on knowledge of the expected amount of noise present in the data. For arbitrary m ∊ N, we present examples in which the optimal decision changes m times as the probability of error in an individual datum increases from 0 to 1/2. Thus, no decision procedure that is insensitive to (or does not know) the amount of uncertainty in the data can perform as well as one that is aware of the unreliability of its data.

Sophia Paleologou

Papers

Method and system for error-free data transfer

Method and system for reliable broadcasting of data files and streams

Decision Making in the Presence of Noise