Importance

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Abstract

A flash solid state disk card comprises a flash memory comprising M block or M blocks and r redundant blocks, and an address conversion table which outputs a physical sector number 1 to N, or 1 to N and (M+1) to (M+r) in correspondence to an input of a logical sector number 1 to N. The number of blocks M is larger than N. If data in a block for a logical sector number (LSN) having a value L, equal to or less than N is updated, another data are erased in a block for a physical sector number (PSN) determined by the address conversion table, the data are written to a free block, and a physical sector number in correspondence to the logical sector number LSN=L in the address conversion table is changed to a number of the block to which the data to be updated are written. If a logical sector number (LSN) having a value L is equal to or less than N, data are read from a block for a physical sector number in correspondence to the logical sector number LSN=L in the table, otherwise data are read from a block for a physical sector number PSN=L. Thus, a flash solid state disk card can be used efficiently for a longer time. Preferably, a substitution table is provided for defective blocks to substitute a block for a defective block.

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First Claim