A method for controlling head loading/unloading operations in a magnetic disk
drive
apparatus that can perform a head retracting operation by using a reserve power
source in order to retract head elements to a predetermined rest position even
when a primary power source has shut down during the operation of the apparatus
has been developed. In order to guarantee proper power off unloading of head elements
at a shutdown time of the primary power source, a system within the magnetic disk
apparatus judges, prior to start the head loading control, whether a sufficient
electric power is secured in a reserve system in order to retract the head elements
to a predetermined rest position if a shutdown of the power source occurs.
