Disclosed is a disk drive that provides for internal disk drive temperature
estimation. The disk drive includes an actuator, a head attached to the actuator,
a disk to store data, a preamplifier connected to the head to amplify read and
write signals, and a processor for controlling operations in the disk drive including
moving the actuator such that the head is moved to read data from and write data
to the disk. The processor under the control of a program is further utilized to
calculate a junction temperature (JTemp) based on a breakthrough voltage
of the preamplifier, apply a filter to the calculated JTemp to compensate
for temperature noise, and to estimate an internal disk drive temperature based
upon the filtered JTemp.