International Business Machines Corporation

Gerard Barucchi

Jean L Calvignac

Daniel Orsatti

Andre G Tracol

Fabrice Jean Verplanken

Gilles Toubol

Olivier Maurel

Philippe Klein

Pierre J Huon

Philippe Cuny

Jean-Luc Peter

Jose Galcera

Philippe Jachimcsyk

The method and apparatus for correcting one B-bit block in error in a memory organized in words comprising N B-bit blocks consist of appending to the data bits to be written into the memory words a limited number of error correction bits computed from a depopulated parity check matrix which gives the capability of only correcting one block in error and improving the memory failure rate by cyclically reading each word, correcting a block found in error if any and writing the corrected data bits with the corresponding error correction bits in place of the read word.

Method and apparatus for correction errors in a memory

An error correction apparatus includes an error control circuit which computes for each burst of a message (for a destination unit) an error correction code as a function of an initial error correction code at the first burst of the message or of the error correction code of the previous burst and of the data bytes of the burst. The burst error correction code is sent on a medium which is separate from the data transport medium as a companion of the burst. Also, the error control circuit receives the burst error correction code from an origin unit and generates the burst error correction code to be compared with the received burst error correction code. If a mismatch is detected, the burst found in error is flagged.

Apparatus for generating and checking the error correction codes of

The system performs an optimized number of simultaneous transfers of data packets between pairs of units comprising an origin unit and a target unit selected among N data processing units (8). Each data processing unit comprises a set of outbound queues with one outbound queue associated with each one of the data processing units to which it may send data packets, for storing the data packets to be sent by the data processing unit to the data processing unit associated with said one outbound queue. The transfers are performed during a time burst Ti+1 by data switch 6 under control of switching control signals sent to data switch by the units on lines 16-1 to 16-N in response to control out signals generated by scheduler 4 during previous burst time Ti. The scheduler runs a selection algorithm which gives each unit an equal probability to be selected as origin unit in a given period.

Switching system for simultaneously transferring data between data

The synchronization circuit resynchronizes the data bits received from remote devices on line or link (20-1) with their own clock CS and frame synchronization signal FS with a central clock CO and central frame synchronization signal FO. The received bits are sequentially arranged in an n-bit cyclic buffer (114-1) with the received bit clock CS. The arranged bits are sequentially picked at the opposite buffer position with the central clock CO. The buffer loading position is provided by binary counter 102 incremented by CS and the buffer picking portion is given by binary counter 100 incremented by CO. At initialization counters 102 and 100 are set to 0 and n/2. The resynchronized data bits on line 21-1 and the resynchronized frame signal FSR on line 61-10 are provided to an additional circuit which synchronize the data bits at the frame level.

Synchronization circuit for a synchronous switching system

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Villeneuve Loubet, France

Gerard Barucchi