Memory system

A memory system comprising:

• a nonvolatile memory that includes a plurality of blocks, each of the plurality of blocks being a unit of a data erase operation and including a plurality of storage locations, each of the plurality of storage locations including a plurality of memory cells;
• and
• a controller electrically connected to the nonvolatile memory and configured to execute a data write operation on a write destination block among the plurality of blocks by using a multi-step program operation that includes at least a first step program operation and a second step program operation, wherein
• the controller is configured to execute the data write operation on the plurality of storage locations of the write destination block in an order in which:
• the first step program operation on a first storage location of the write destination block is executed;
• after completion of the first step program operation on the first storage location, the first step program operation on a second storage location of the write destination block is executed;
• in response to completion of the first step program operation on the second storage location, the second step program operation on the first storage location is executed;
• and
• after completion of the second step program operation on the first storage location, the first step program operation on a third storage location of the write destination block is executed, wherein
• the controller is further configured to:
• in executing the data write operation on the write destination block according to the order, manage first information indicating whether each of one or more storage locations of the plurality of storage locations of the write destination block is in a first state in which the first step program operation is completed and the second step program operation is not started yet by:
• updating, in response to completion of the first step program operation on a storage location of the write destination block, the first information so that information indicating that the first step program operation has been completed on the storage location is added to the first information;
• and
• updating, before starting the second step program operation on a storage location of the write destination block, the first information so that information indicating that the second step program operation is to be started on the storage location is deleted from the first information;
• and
• store the updated first information to the nonvolatile memory.