US Patent 8001319 Semiconductor storage device

A semiconductor storage apparatus is coupled with a system bus to receive a write request accompanied with first and second blocks of data, which are stored in nonvolatile semiconductor memories. A control device sends a first erase command to one of the nonvolatile memories to initiate a first internal erase operation of data within the nonvolatile memories. After the first erase command has been sent, the control device sends a second erase command to another one of the nonvolatile memories, to initiate a second internal erase operation of data within the other nonvolatile memory.