Memory system and operating method thereof

A memory system comprising:

• a memory controller configured to receive commands and write data corresponding to the commands from a host, queue the received commands, and output the queued commands and the write data;
• and
• a nonvolatile memory device configured to perform operations in response to the commands and the write data, which are output from the memory controller, and outputs an operation completion signal to the memory controller when the operations are completed,
• wherein, when a flush command is received, the memory controller releases the write data temporarily stored after the write data are transmitted to the nonvolatile memory device.

A method for operating a memory system, the method comprising:

• queuing commands received from a host, and temporarily storing write data corresponding to the commands in a controller buffer memory;
• performing operations by transmitting the queued commands and the write data stored in the controller buffer memory to a nonvolatile memory device;
• when a flush command is received from the host, queuing the flush command next to the queued commands and releasing the write data temporarily stored in the controller buffer memory;
• and
• queuing, next to the flush command, new commands received from the host after the flush command is received, and temporarily storing new write data corresponding to the new commands in the controller buffer memory from which the write data are released.