A method for operating a memory system is provided. In this method, a write command is received to write data following a previous write command. The write command and the previous write command have a discontinuity in logical addresses and the discontinuity in logical addresses defines a gap between a logical address of the write command and a logical address of the previous write command. Here, a sequential update block and preexisting data associated with the sequential update block are provided. The gap is compared with a threshold size and the data are written to the sequential update block if the gap is less than the threshold size.