This is a well made video, but the technologies described are completely obsolete.
The inductive read element has been discarded in the 90s and the longitudinal media shown was replaced by 2006.
Also PRML channels are long gone, actually they originally were created to boost phone line mode performance in the late eighties.
Modern actuators combine VCM and piezzo technologies.
Recent head technology actively manages fly height via thermal profile control.
It's time for an update.