Magnetic disk device and method

A magnetic disk device comprising:

• a magnetic disk including a first plurality of storage areas arranged in a radial direction;
• a magnetic head configured to write or read data to or from the magnetic disk;
• a memory configured to store a plurality of counters that is a group of counters respectively corresponding to the first plurality of storage areas;
• and
• a controller configured to:
• set an increment amount for each of the plurality of counters;
• increment a value of a first counter by an increment amount related to the first counter according to a write operation of writing data to the magnetic disk, the first counter being a counter of the plurality of counters corresponding to a first storage area, the first storage area being a storage area in a vicinity of a first position that is a position where data is written by the write operation;
• execute an operation of calculating a remaining number of write times, which is a number of write operations for a vicinity of one storage area that are executable until a value of a counter corresponding to the one storage area reaches a first threshold value, based on an increment amount for the one storage area, for each of a second plurality of storage areas that is some or all of the first plurality of storage areas;
• execute a rewrite operation on each of the second plurality of storage areas in an order according to the remaining number of write times in an idle state, the rewrite operation being an operation of reading all data from one storage area and writing all the read data to the one storage area;
• and
• reset, among the second plurality of storage areas, a value of a counter corresponding to a storage area on which the rewrite operation has been executed.