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System for transferring digital data between a host device and a recording medium

  • US 4,672,613 A
  • Filed: 11/01/1985
  • Issued: 06/09/1987
  • Est. Priority Date: 11/01/1985
  • Status: Expired due to Term
First Claim
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1. A system for transferring digital data between a host device and a target recording medium, comprisinga buffer memory having a matrix of storage locations for storing digital data;

  • a write interface unit for transferring data to a target recording medium for recording;

    a read interface unit for reading and processing data from a target recording medium; and

    a buffer interface control unit for transferring data from the host device to the buffer memory and from the buffer memory to the write interface unit during a writing mode of operation, and for transferring data from the read interface unit to the buffer memory and from the buffer memory to the host device during a retrieval mode of operation, wherein the buffer interface control unit comprisesmeans for generating error correction code characters pertaining to said data as said data is being transferred to the buffer memory; and

    a host direct memory access (DMA) unit for transferring the data from the host unit to the buffer memory, and for transferring the generated error correction code characters to the buffer memory; and

    a target DMA unit for transferring the data and the error correction codes from the buffer memory to the write interface unit;

    wherein the host DMA unit includes means for accessing a first set of prescribed noncontinuous buffer memory storage locations during the writing mode of operation in order to store the data transferred from the host unit in the buffer memory in a predetermined buffer format that includes additional sets of prescribed storage locations interspersed with the first set of data storage locations for the storage of error code characters pertaining to said data, and means for accessing one of the additional sets of prescribed storage locations during the writing mode of operation in order to store the error correction code characters so that they are interspersed with the data in the predetermined buffer format; and

    wherein the target DMA unit includes means for accessing the first set and the one additional set of prescribed buffer memory storage locations in a predetermined noncontinuous sequence in order to retrieve the data and the error correction code characters from the buffer memory in a format that includes open time slots interspersed with time slots occupied by the retrieved data and error correction code characters for the insertion of error detection code characters pertaining to the retrieved data and error correction code characters.

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