hard drive head/seek motor with Arduino?
As snoopen says - you want a &quot;voice coil&quot; driver or actuator.
It's well within the capabilities of an Arduino to drive one of these.
There are a number of people offering on-web examples of HDD voice coil drivers used for other purposes.
Wikipedia overview
This provides a general view of an HDD voice coil actuator
This is an actuator withy the magnets in position above and below the coil

and here is a unit with the magnets moved out of position to provide an internal view.

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Here is an utterly amazing LASER shutter driver achieving mechanical shutter rise times of
500 nS !!!.  There are a number of links off this page to other variants and upgrades.
Their basic driver circuit is suitably simple -

Here is a formal 2004 paper based on the above
And three years later in 2007, an updated version

Here is a throttle position control using an HDD actuator.
Circuit diagram here - the actual actuator control is the middle third hozizontally and the actual driver is 2 transistors driven by an opamp. An Arduino could easily feed a s signal to such a circuit. eg smoother PWM or a DC voltage generated in some other manner.