Repeatable run out compensation

Abstract

An apparatus can include a disk drive controller that includes at least one repeatable run out (RRO) compensator corresponding to a RRO component, the disk driver controller configured to change a head assembly position, and to disable the at least one RRO compensator in response to the head assembly position changing from one predetermined area of a disk to at least one other predetermined area of the disk

What is claimed is: 
     
         1 . An apparatus, comprising:
 a disk drive controller that includes at least one repeatable run out (RRO) compensator corresponding to a RRO component, the disk driver controller configured to change a head assembly position, and to disable the at least one RRO compensator in response to the head assembly position changing from one predetermined area of a disk to at least one other predetermined area of the disk.   
     
     
         2 . The apparatus of  claim 1 , wherein:
 the at least one RRO compensator includes a plurality of RRO compensators.   
     
     
         3 . The apparatus of  claim 2 , wherein:
 each RRO component corresponds to a multiple of the frequency at which the disk rotates.   
     
     
         4 . The apparatus of  claim 2 , wherein:
 the disk driver controller is further configured to operate at least one other RRO compensator in response to the head assembly position changing from the one predetermined area to at least the other predetermined area of the disk.   
     
     
         5 . The apparatus of  claim 2 , wherein:
 the disk drive controller is configured to disable a plurality of RRO components in response to the head assembly position changing from the one predetermined area of the disk to the other predetermined area of the disk.   
     
     
         6 . The apparatus of  claim 1 , wherein:
 the one predetermined area includes an area within a predetermined diameter of the disk, and   one other predetermined area includes an area outside of the predetermined diameter.   
     
     
         7 . The apparatus of  claim 1 , wherein:
 the head assembly is includes any selected from the group of: a read head assembly to read data from the disk, a write head assembly to write data to the disk, and a read/write head assembly to read data from the disk and write data to the disk.   
     
     
         8 . The apparatus of  claim 1 , wherein:
 the controller comprises any selected from the group of: a digital signal processor, a micro-processor, and a micro-controller.   
     
     
         9 . An apparatus, comprising:
 an arm configured to move across a disk in response to electrical signals; and   a controller configured to control the electrical signals, and including at least a first compensator configured to compensate for irregularities in the disk, the controller further configured to stop the first compensator if the arm is to move from one disk area to at least one other disk area.   
     
     
         10 . The apparatus of  claim 9 , wherein:
 the first compensator compensates for deformations of the disk.   
     
     
         11 . The apparatus of  claim 9 , wherein:
 the disk includes data storage tracks; and   the controller further includes at least a second compensator configured to compensate for eccentricities of the storage tracks; wherein   the controller does not stop the second compensator if the arm is to move from the one disk area to at least the other disk area.   
     
     
         12 . The apparatus of  claim 9 , wherein:
 the disk includes at least an inner diameter (ID) area and an outer diameter (OD) area, and the controller is configured to stop the first compensator if the arm is to move from the ID area to the OD area.   
     
     
         13 . The apparatus of  claim 9 , wherein:
 the disk is configured to rotate at a frequency; and   the controller includes a plurality of compensators, each corresponding to a multiple of the frequency.   
     
     
         14 . The apparatus of  claim 13 , wherein:
 the first compensator corresponds to no less than four times the frequency.   
     
     
         15 . The apparatus of  claim 9 , wherein:
 the arm rotates about a pivot point and includes a head assembly at a distal end to read data from or write data to the disk.   
     
     
         16 . A method, comprising:
 positioning a head assembly with multiple compensators that compensate for disk irregularities; and   stopping at least one the compensators when moving the head assembly from one disk area to at least one other disk area.   
     
     
         17 . The method of  claim 16 , further including:
 the compensators include
 at least one first compensator that compensates for deformations in the disk, and 
 at least one second compensator that compensates for eccentricities in data tracks in the disk; and 
   stopping the first compensator and maintaining the second compensator when moving the head assembly from the one disk area to the at least other disk area.   
     
     
         18 . The method of  claim 16 , further including:
 each compensators corresponds to a multiple of a disk rotation speed.   
     
     
         19 . The method of  claim 16 , further including:
 restoring the first compensator after the head assembly has moved from the one disk area to the other disk area.   
     
     
         20 . The method of  claim 16 , further including:
 determining if a current position of the head assembly is in the one disk area; and   receiving a command; and   determining if the command is to move the head assembly to the other disk area.