Magnetic disk drive with function assignment and manufacturing method therefor

A disk drive comprising:

• a disk;
• a head that accesses the magnetic disk;
• a nonvolatile memory that stores a function assignment program;
• a processor that executes the function assignment program;
• and
• a state setter that, when electric power is supplied to the processor, sets up states for the processor to refer to and correspondingly judge whether the processor is to execute the function assignment program.

A manufacturing method for a disk drive equipped with a recording medium having a function assignment program stored thereon, and with a processor for executing the function assignment program, the manufacturing method comprising:

• assembling the disk drive into a host apparatus;
• performing operational tests on the host apparatus;
• and
• causing the processor to execute the function assignment program in at least one part of a period during which the host apparatus is being subjected to operational testing.