A disk drive includes a rotatable data storage disk, a transducer, and a
controller. The transducer is configured to write data on the disk. The
controller is configured to receive data from a host device, to measure
at least one parameter that is indicative of a time varying
characteristic associated with the disk drive, and to write the measured
parameter and the data on the disk through the transducer. The time
varying characteristic that is measured may include temperature, air
pressure, flying height of the transducer relative to the disk, and/or a
position error signal (PES) that is indicative of a radial location of
the transducer relative to a desired location along a track on the disk.
The measured parameters may be embedded within the data that is written
on the disk, they may be written in a same track and/or sector as the
data, and/or they may be written on a reserved portion of the disk.