Memory system and control method

A method for controlling a memory system comprising:

• a nonvolatile memory;
• and
• a memory controller including:
• a host interface configured to communicate with a host in accordance with a first interface protocol, according to which write data is communicated in units of a sector having a first size;
• a memory interface configured to communicate with the nonvolatile memory in accordance with a second interface protocol, write data is communicated in units of a second size greater than the first size;
• and
• a write buffer configured to temporarily store data of a third size in each of a plurality of entries thereof, each of the entries being reserved to store data of a plurality of sectors that are associated with a continuous logical address range, the third size being equal to the second size or 1/N of the second size, N being a natural number, each of the plurality of sectors having the first size, the method comprising:
• selecting one of the entries in which write data is to be stored;
• determining whether the selected entry is missing data of any sector;
• in response to determining that the selected entry is missing data of at least one sector, performing a host inquiry by transmitting a request to the host for the missing data via the host interface;
• in response to receiving the missing data from the host via the host interface, storing the missing data in the selected entry;
• and
• when the selected entry is not missing data from any of the sectors, performing a write operation to store the data of the second size in the selected entry into the nonvolatile memory at a continuous physical address range thereof.