Memory system

A memory system comprising:

• a first semiconductor memory storing block management information that includes a valid cluster counter;
• a second semiconductor memory that includes a plurality of blocks each including a plurality of clusters;
• and
• a controller including:
• a memory controller configured to interface with the first semiconductor memory, and to update the valid cluster counter of the block management information;
• and
• a block management unit configured to generate an update instruction to update the number of valid clusters associated with a block in which data is to be written, according to a write request received from a host, and to transmit the instruction to the memory controller,
• wherein the memory controller and the block management unit are packaged as part of the controller, and the first semiconductor memory and the second semiconductor memory are disposed outside of the controller.

A method for managing a memory system comprising a first volatile semiconductor memory, a second nonvolatile semiconductor memory that includes a plurality of blocks each including a plurality of clusters, and a controller, the method comprising:

• storing management information in the first volatile semiconductor memory in which identification information of the blocks and corresponding numbers of valid clusters of the blocks are stored and respectively associated with each other;
• generating an update instruction to update the number of valid clusters associated with a block in which data is to be written, according to a write request received from a host;
• reading, from the first volatile semiconductor memory, the number of valid clusters corresponding to the update instruction;
• updating the read number of valid clusters by an update amount corresponding to the update instruction;
• and
• writing the updated number of valid clusters back to the first volatile semiconductor memory.