Patent ID: 8755142

Claim:
A magnetic recording disk drive comprising: a magnetic recording disk having a recording surface with a plurality of concentric data tracks and a plurality of servo sectors extending generally radially across the tracks, the servo sectors containing position error signal (PES) fields; a write head associated with said disk surface for generating a magnetic write field to write data to the tracks; a read head for reading data written in the tracks and for detecting the PES fields; servo control electronics for generating a PES in response to the PES fields detected by the read head; an actuator connected to the heads for positioning the write head to a target track for writing and maintaining the write head on said target track in response to the PES from the servo control electronics; a controller for controlling the writing of data by the write head to the tracks, the controller being operable in a normal mode wherein data is written to a target track if the PES does not exceed a first predetermined positive or negative write inhibit threshold (WI- 1 ), wherein a positive WI- 1 is associated with a first track radially adjacent the target track and a negative WI- 1 is associated with a second track radially adjacent the target track and radially opposite the first radially adjacent track; and memory coupled to the controller and containing a program of instructions readable by the controller for operating in a high track misregistration (TMR) mode wherein data is written to the target track if the PES exceeds a positive or negative WI- 1 , the program of instructions undertaking the method acts comprising: (a) writing data intended to be written to a target track to memory; (b) reading data from tracks adjacent said target track and writing said adjacent track data in memory; (c) writing said data intended to be written to said target track to said target track; (d) if the PES during writing of data to said target track exceeds a second positive or negative predetermined write inhibit threshold (WI- 2 ), wherein a positive WI- 2 is associated with said first adjacent track and a negative WI- 2 is associated with said second adjacent track, identifying the first or second adjacent track as an encroached adjacent track from the positive or negative WI- 2 exceeded, and flagging the encroached adjacent track as the target track for writing; and reading from memory data for said encroached adjacent track, and repeating steps (b) through (d) for said flagged encroached adjacent track.