Determining head position during a head switch using multiple index codes

摘要

An embodiment of the present invention may be described as a method of determining a disc drive head position over a data surface during a head switch operation. The method includes switching from a first head located over a first data surface on one disc to a second head located over a second data surface on a different disc. Each data surface has non-index servo sectors interspersed between a plurality of index servo sectors defined thereon, and each index servo sector has a unique index code corresponding to its angular track position. The method also includes reading an index code from an index servo sector on the second surface and determining an index servo sector number from the index code. Additionally, the method includes incrementing the servo sector number as the second head encounters subsequent servo sectors. A disc drive includes data storage discs arranged in a disc stack. The disc drive is adapted to ascertain head position following a head switch between a first head positioned over a first data surface on one disc and a second head positioned over a second data surface on a different disc utilizing a plurality of index servo sectors defined on the second data surface.