hdd using variably controlled e g configured estimator s and or controller s where such variable control configuration is performed in relation to a read mode of operation and a write mode of operation in one embodiment of the invention the estimator s and or controller s within the hdd may be conventionally configured and operated during write operations that is a write head may be conventionally controlled in its track positioning during write operations in view of a defined positioning tolerance this defined positioning tolerance will take into account as needed the expected amplitude of a position error signal pes provided by the disk of the hdd however estimator s and or controller s within the hdd may be differently configured in embodiments of the invention during read operations that is despite the strict positioning tolerance applied to the write head during write operations the read head may be positioned with a reduced tolerance thereby allowing faster read operations and reducing constraints on the read operation of the hdd as a result read operations will enjoy reduced susceptibility to operating disturbances even though the amplitude of the constituent pes is reduced in the description that follows it is assumed that the amplitude margin provided by a pes is relatively small during write operations and relatively large during read operations.