Adjusting track density and bit density to provide limited excess capacity in a storage device

A data storage device for storing data on one of a plurality of storage surfaces, the storage device comprising:

• a plurality of heads, each head capable of reading from and writing to a storage surface at a head-specific bit density and a head-specific track density;
• and
• a controller for controlling the position of the heads based in part on the track density for each head and for controlling the rates at which the heads write to and read from the storage surfaces based in part on the bit density for each head, the track densities and bit densities together forming storage densities that are defined through a processes comprising:
• selecting a desired capacity for the storage device;
• determining initial data storage densities associated with each head, the initial data storage densities comprising an initial bit density and an initial track density;
• determining a total initial capacity for the storage device based on the initial data storage densities;
• selecting a desired capacity for the storage device, thereby defining an initial excess capacity, if any, as the total initial capacity in comparison to the desired capacity;
• adjusting at least one of the initial data storage densities so that the data storage devices has an adjusted capacity defining an adjusted excess capacity in comparison to the desired capacity, the adjusted excess capacity being less than the initial excess capacity, if there is an initial excess capacity.