Servo write method and servo write system for hard-disk drive

A servo write system for a hard-disk drive, said system comprising:

• a self-servo write apparatus comprising:
• an external interface for connection with a database;
• an MPU which controls a said system;
• a memory for temporarily retaining data;
• a read/write channel which transmits a read signal and receives a write signal;
• and
• a motor driver control unit which controls a spindle motor and a VCM;
• a yield database in which data indicating a relationship between a part characteristic and a yield is stored, said yield database being connected to said self-servo write apparatus;
• a serial number reader;
• and
• said hard-disk drive comprising:
• a plurality of magnetic-recording disks;
• and
• a plurality of magnetic-recording heads corresponding to recording surfaces of said plurality of magnetic-recording disks;
• wherein said yield database accumulates a past relationship between characteristics of a magnetic-recording head and a magnetic-recording disk which are incorporated into said hard-disk drive and a yield of said hard-disk drive;
• said self-servo write apparatus predicts said yield which is obtained when each of all said magnetic-recording heads is used as a position control head in a combination of said plurality of magnetic-recording surfaces and said corresponding magnetic-recording heads;
• and the self-servo write apparatus selects a magnetic-recording head having a highest predicted yield of said plurality of magnetic-recording heads, and performs a self-servo write.