Patent ID: 7388792
Filing Date: 2008-06-17
Classification: G11C

Abstract:
1. A method of operating a memory system to be used by a host device, the memory system having a nonvolatile semiconductor memory including a plurality of blocks, and the memory system being configured to permit data to be erased in units of one block, the method comprising: relating an address of a first block to an address range of data stored in the first block in units of one block; receiving an erase command which requests erasing part of the data stored in the first block, from the host device; canceling a relation between the address of the first block and an address range of the part of the data in response to the erase command while maintaining the relation between the address of the first block and the address range of remaining data stored in the first block; outputting a signal indicating that an erase operation requested by the erase command is completed, to the host device; receiving a read command which requests reading data that has an address range included in the address range of the part of the data, from the host device, after canceling the relation; and outputting an initial-value data to the host device in response to the read command.