"WDC has moved the final joint closer to the read/write head and called it a multi-stage micro actuator with finer track positioning capability."
quick search of Google.com/patents shows:
Multi-stage actuator with writer position determination capability
April 28, 2015
Inventors Ximin Shan, Jye Kai Chang, Sandeep Sequeira
Original Assignee Seagate Technology Llc
Filed: April 30, 2014
Seagate? hmmm, i thought we were talking about WDC here.