A data storage system has a plurality of individual data storage units, each of which can undergo unpredictable independent failure. By dividing data blocks to be stored therein into a number of sub-blocks one or more less than the number of data storage units and creating a redundant data sub-block of the type permitting reconstruction of any one sub-block of data using the remaining sub-blocks and the redundent sub-blocks, and then storing each of the data sub-blocks and the redundant sub-block on a different one of the data storage units, it is possible to reconstruct any one failed data sub-block of a related group using the other sub-blocks. It is necessary to be able to detect the failure of the sub-block, and the preferred way is by a multibit error detection code appended to each sub-block, or by failure sensed within and by an individual data storage unit. The system is preferably implemented with disk drives functioning as the data storage units in view of the well-known tendency of such devices to occasionally generate an error which prevents reading a previously written record on one of them.

Data error correction system

A relatively large plurality of relatively small, independently operating disk subsystems are coupled to a read/write interface containing error circuitry and data organizer circuitry. The data organizer circuitry organizes read/write data for read/write communication with the disk subsystems via the error circuitry such that the overall system appears as a large, high capacity disk system having an unusually high fault tolerance and a very high bandpass.

High capacity disk storage system having unusually high fault tolerance level and bandpass

A method of interleaving data for transmission is provided wherein first (106) and second (108) interleaving patterns for arranging data symbols in a source data stream (110) into first (106) and second (108) transmitted data streams are selected. Each of said data symbols has at least one bit. The first (106) and second (108) transmitted data streams are transmitted substantially simultaneously on separate transmission channels (102 and 104) to at least one receiver. The first (106) and second (108) patterns are used to transmit the data symbols in the source data stream (110) in a different order on the respective transmission channels (106 and 108) to maximize recovery of the source data stream (110) when the transmission channels (106 and 108) are blocked. The selected interleaving patterns can involve reordering the data symbols throughout the first (106) and second (108) transmitted data streams (106 and 108) using different reordering criteria. The reordering criteria can vary on a frame-by-frame basis if the source data stream (110) is time division multiplexed. Complementary data can be sent on respective transmission channels (102 and 104).

Method and apparatus for continuous cross-channel interleaving

A method and apparatus for convolutionally encoding (30) and interleaving (46, 48) a source data stream for transmission on one or more transmission channels (66, 68). Convolutionally encoded data groups (36) are time-interleaved (46) to disperse selected bits of puncture groups (45) in the data groups, bits in between data groups, and bits in selected sets of data groups, facilitating reconstruction of the source data from at least a portion of the interleaved data received on at least one transmission channel. The time-interleaving functions (46) are selected to facilitate reconstruction of the source data from one transmission channel following continuous blockage. Puncture groups are selected to allow reconstruction of the source data using a minimum number of puncture group bits. Multiple combinations (44a-44d) of puncture group bits can be used to reconstruct the source data following blockage of one channel. A Viterbi decoder (26) performs decoding.

Method and apparatus for concatenated convolutional encoding and interleaving

This invention relates to a digital signal encoding apparatus in which the .[.width of the range in.]. .Iadd.digital signal is divided into frequency components in plural frequency bands and the bandwidth of the frequency bands is .Iaddend.selected to be wider for .[.the.]. higher .[.frequency range.]. .Iadd.frequencies .Iaddend.of the digital .[.signals divided into a plurality of regions.]. .Iadd.signal .Iaddend.and in which the encoded signals are synthesized for the respective .[.ranges.]. .Iadd.frequency bands .Iaddend.wherein encoding is controlled as a function of the output detecting the characteristics of the .Iadd.frequency .Iaddend.components .[.of.]. .Iadd.in .Iaddend.the .[.divided.]. frequency .Iadd.bands .Iaddend.and the detection time interval is selected to be longer for the lower frequency .Iadd.bands .Iaddend.to enable more efficient encoding to be performed as a function of the properties of input digital signals.

Method and apparatus for encoding audio signals divided into a plurality of frequency bands

Described is a method for PCM signal recording in which, when single-channel or multichannel PCM signals are recorded so that one-channel PCM signals are recorded in plural recording tracks, the input PCM signals of one channel are correspondingly distributed to the plural recording tracks with at least one word as a unit, and in which the distributed plural signals are subjected to an encoding operation independently of one another and are recorded on the plural recording tracks. In distributing the input PCM signals by word units, word groups consisting of a predetermined number of consecutive words are sequentially distributed to the recording tracks, or plural consecutive words equal in number to the number of recording tracks are distributed to the tracks. In encoding, the input words are separated as a function of whether the input word numbers are odd or even, and the words thus separated are subjected to time delaying or interleaving operations, after which the odd and even number words are synthesized.

Method of recording odd and even words of one channel PCM signals in plural tracks

Groups of primary multi-bit digital signals arranged in digital words are spaced apart in sequence and are interleaved with related groups of secondary multi-bit digital signals, each of which is derived from, and encodes substantially the same information as, one of the primary signals. To minimize errors in processing signals, either the primary signals are delayed relative to the secondary signals, or vice versa, before they are interleaved. Cyclic redundancy check code signals are derived for each group of primary signals and each group of secondary signals and are interleaved in sequence with the primary and secondary signals. At a further stage in processing the signals, the checked code signals are analized and the related pairs of primary and secondary signals, which have been brought back into coincidence, are checked to determine whether one or both of the primary and the secondary signals of each related pair has been processed without error. If only one of the signals has been processed without error, that signal is selected for further processing. If both signals have been processed without error a predetermined one of them is selected for further processing. If neither one of them has been processed without error, the immediately preceding signal that was selected may be selected a second time. In order to incorporate all of the signals in the most convenient format, the secondary signals may comprise only the higher bit orders of the primary signals, eliminating some of the lower bit orders as containing unnecessarily detailed information. The number of bits thus omitted preferably causes a group of secondary signals plus the cyclic redundancy check code signals for that group and for the related primary group to equal the total number of bits of that primary group.

Digital signal transmission method

In this PCM signal recording method, when PCM signals for at least one channel are recorded on a plurality of recording tracks for each channel, the input PCM signals for one channel are distributed according to the plurality of recording tracks with at least one word taken as a unit, and then these distributed signals are each encoded independently and are recorded on the corresponding recording tracks. Examples of means for distributing the input PCM signals in one ore more word-units include a means for successively distributing the PCM signals to the corresponding recording tracks for a predetermined number of consecutive words, and a means for successively distributing to the corresponding recording tracks a plurality of consecutive words equal to the number of recording track per channel. This encoding processing is such that the input words are separated according to whether the input sequence thereof is odd or even, and odd and even words are each delayed, are provided with independent sign error correction codes, and are interleaved before being synthesized.

Claudia Brandes

Papers

Method of recording odd and even words of one channel PCM signals in plural tracks

Digital signal transmission method

Method of recording pcm signal