Importance

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Abstract

A semiconductor storage device such as a disk pack includes a plurality of flash memories, a write buffer memory in which data are temporarily held, a processor which controls data writing and erasing operations and which transfers and analyzes commands and statuses to and from the flash memories, and a circuit which generates a writing supply voltage Vpp, different from a reading supply voltage, for the flash memories. The processor operates to send a first instruction for writing or erasing data of one word into a first one of the flash memories, and it continuously writes the data of one word into an accessible one of the other flash memories before the first one of the flash memories becomes capable of accepting the next write or erase instruction. The processor determines whether each nonvolatile memory has individually become ready to accept a new write or erase instruction. A plurality of instructions for writing or erasing data for consecutive addresses may thus be distributively, e.g., sequentially, fed to the plurality of nonvolatile memories to reduce a time period for writing or erasing data. The semiconductor storage device further includes a static random access memory for storing a conversion table for converting logical sector numbers into physical sector numbers for those areas of the flash memories which have accepted the write and erase instructions. The semiconductor disk pack may be connected, for example, to a standard bus in a personal computer.

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First Claim