Head loading and unloading method and device

A method for repositioning a read/write head from a position adjacent a surface of a magnetic disk to a parking location having reduced audible noise, the read/write head disposed on an actuator arm having a voice coil motor, comprising:

• receiving a read/write head unload signal;
• applying a first current pulse to the voice coil motor in response to the read/write head load signal, the first current pulse having a first amplitude and a first duration;
• determining a read/write head velocity in response to the first current pulse;
• comparing the read/write head velocity to a desired read/write head velocity to form a difference velocity;
• determining a second amplitude and a second duration for a second current pulse in response to the difference velocity, the second duration different from the first duration and the second amplitude different from the first amplitude;
• and
• applying the second current pulse to the voice coil motor.

A system having a storage device including a magneto-resistive head for repositioning the magneto-resistive head, the storage device further comprising:

• an actuator arm having a voice coil motor disposed on one end and the magneto-resistive head disposed on another end, the voice coil motor for generating a back electromotive force;
• a voice coil motor driver coupled to the voice coil motor for applying a first current pulse to the voice coil motor, the first current pulse having a first amplitude and a first duration;
• a first processor coupled to the voice coil motor and to the voice coil motor driver for determining a difference between the back electromotive force voltage and a predetermined back electromotive force voltage, and for determining a second amplitude in response to the difference, the second amplitude different from the first amplitude;
• and
• a second processor coupled to the first processor for determining a second duration, the second duration different from the first duration,
• wherein the voice coil motor driver is also for applying a second current pulse to the voice coil motor, the second current pulse having the second amplitude and the second duration.

A method for repositioning a read/write head from a position adjacent a surface of a magnetic disk to a parking location with reduced audible noise, the read/write head disposed on an actuator arm having a voice coil motor, comprising:

• receiving a read/write head unload signal;
• applying a series of current pulses to the voice coil motor in response to the read/write head unload signal until the read/write head reaches the parking location, each current pulse having an amplitude and a duration;
• after a first number of current pulses, determining a back electro-motive force voltage in the voice coil motor;
• determining a read/write head velocity in response to the back electro-motive force voltage;
• determining a difference between the read/write head velocity and a desired read/write head velocity;
• and
• using the difference between the read/write head velocity and the desired read/write head velocity to determine a duration for each of a next first number of pulses,
• wherein no two consecutive pulses in the series have the same duration.

A method for repositioning a read/write head from a parking location to a position adjacent a surface of a magnetic disk with reduced audible noise, the read/write head disposed on an actuator arm having a voice coil motor, comprising:

• receiving a read/write head load signal;
• applying a series of current pulses to the voice coil motor in response to the read/write head load signal until the read/write head reaches the position adjacent a surface of a magnetic disk, each current pulse having an amplitude and a duration;
• determining a read/write head velocity in response to the back electro-motive force voltage;
• determining a difference between the read/write head velocity and a desired read/write head velocity;
• and
• using the difference between the read/write head velocity and the desired read/write head velocity to determine a duration for each of a next first number of pulses,
• wherein no two consecutive pulses in the series have the same duration.