Ann: 4DS Technical Update, page-298

I don't see HGST/WD as a "suitor" - they are a development partner with a right of access to the IP.

I haven't been in 4DS so long as to remember the inking of the JDA between 4DS and WD, but I'm assuming 4DS took the tech and their plans to a bunch of semi-conductor manufacturers to secure joint development support. From a bunch of proposals I'm guessing they took the HGST option as it was the most attractive. It certainly doesn't lock them into any sort of exclusivity with WD or preclude them from going elsewhere if they want. Clearly the relationship is working for 4DS as they are happy to renew it every year (as is HGST)