US Patent 7688540 Disk drive selecting TPI profile by estimating head geometry

A disk drive is disclosed comprising a disk and a head actuated radially over the disk. The head is positioned over a first radial location, and a first data tracks per inch (TPI—1) is selected for data tracks recorded near the first radial location. The head is positioned over a second radial location, and a second data tracks per inch (TPI—2) is selected for data tracks recorded near the second radial location. The head is positioned over a third radial location, and a third data tracks per inch (TPI—3) is selected for data tracks recorded near the third radial location. A geometry of the head is estimated in response to TPI—1, TPI—2 and TPI—3.