Magnetic disk apparatus, controller and data processing method

A controller configured to control data to be read from and written to a magnetic disk, comprising:

• a read/write (RW) channel module having an internal memory and configured to process data to be read from and written to the magnetic disk;
• a transfer controller configured to control data transfer between a host apparatus and the RW channel module;
• and
• a processor configured to control the RW channel module and the transfer controller
• wherein
• the transfer controller controls data transfer to and from a buffer memory temporarily storing read data and write data, the host apparatus, and the RW channel module;
• the processor is further configured to:
• read predetermined area data including to-be-rewritten data from the magnetic disk, subject the read predetermined area data to error correction processing in the RW channel module, and store resultant data in the internal memory;
• store rewrite data from the host apparatus in the buffer memory via the transfer controller;
• transfer the rewrite data stored in the buffer memory to the RW channel module, and rewrite, with the rewrite data, the to-be-rewritten data of the predetermined area data stored in the internal memory to thereby update the predetermined area data;
• update, in the RW channel module, the predetermined area data stored in the internal memory using the rewrite data;
• and
• add an error correction code to the updated predetermined area data in the RW channel module, and write resultant data to the magnetic disk.

A data processing method of a controller for controlling data to be read from and written to a magnetic disk, comprising:

• processing data to be read from and written to the magnetic disk, using a read/write (RW) channel module having an internal memory;
• and
• controlling data transfer between a host apparatus, the RW channel module and the magnetic disk,
• wherein the controlling the data transfer includes:
• controlling data transfer to and from a buffer memory temporarily storing read data and write data, the host apparatus, and the RW channel module;
• reading predetermined area data including to-be-rewritten data from the magnetic disk, subjecting the read predetermined area data to error correction processing in the RW channel module, and storing resultant data in the internal memory;
• storing rewrite data from the host apparatus in the buffer memory;
• transferring the rewrite data stored in the buffer memory to the RW channel module, and rewriting, with the rewrite data, the to-be-rewritten data of the predetermined area data stored in the internal memory to thereby update the predetermined area data;
• updating, in the RW channel module, the predetermined area data stored in the internal memory using the rewrite data;
• and
• adding an error correction code to the updated predetermined area data in the RW channel module, and writing resultant data to the magnetic disk.