Abstract: A method for identifying victim tracks distanced from an aggressor track in a hard disk drive that are deleteriously affected by long range fringe effects causing adjacent track interference (ATI) when the aggressor track is written includes writing first and second frequencies to candidate victim tracks, and writing a third frequency to the aggressor track. The amplitudes of the remaining frequencies are read and output and if desired normalized as an indication of ATI to distant victim tracks. Or, data can be written and on-track error rates (OTER) used to determine ATI.

Abstract: An MR read transducer is provided which has a central region located between a pair of end regions. The central region and the pair of end regions extend along a width of the MR read transducer. An MR layer extends along the width of the MR read transducer and has an active layer portion located between a pair of passive layer portions, the active layer portion being located in the central region and each passive layer portion being located in a respective end region. A layer is located in the central region and magnetostatically coupled to the active layer portion of the MR layer for transversely biasing the MR layer. Each passive layer portion of the MR layer is permeable so that it is responsive to externally applied magnetic fields.