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Method and apparatus for management of faulty data in a raid system

  • US 5,913,927 A
  • Filed: 12/15/1995
  • Issued: 06/22/1999
  • Est. Priority Date: 12/15/1995
  • Status: Expired due to Term
First Claim
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1. An apparatus for managing faulty data in a multichannel memory system having a memory array controller for controlling access to the memory system, for memory failure detection, for memory error detection, and for reconstruction of a failed memory channel, the memory system having at least three memory channels where each channel includes one or more modules, each module having a failure and read error detection means, and each memory module being separately replaceable upon failure, the apparatus, accessible to the memory controller, comprising:

  • a) a bad data table (BDT) for storing addresses of non-recoverable data blocks in a replacement memory module, where the replacement memory module stores data reconstructed from a failed first memory module in the memory system, and addresses of other non-recoverable data blocks associated with other memory modules in the memory system, the non-recoverable data blocks arising upon an occurrence of a fault in a second memory module in the memory system prior to completion of reconstruction and storage of data in the replacement memory module;

    b) a write circuit operable after the initiation of a reconstruction of a failed first memory module for writing filler data to a bad block location in the second memory module when a fault is detected in the second memory module during reconstruction of data stored in the first memory module, for writing filler data to an associated location in the replacement memory module and for writing to the BDT addresses of bad data blocks representing non-recoverable data; and

    c) detection circuitry for detecting memory access requests to addresses stored in the BDT, for returning a non-recoverable data error signal to a host system if the access request is a read request, and, if the access request is a write request, permitting the write to the BDT listed address and deleting the listed address from the BDT.

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