I'm pretty sure that there were such drives more than twenty years ago (not popular though). I have to ask, what's the point today? The average latency goes down at most linearly with the number of actuators. One would need thousands to match SSDs. For anything but pure streaming (archiving), spinning rust seems questionable.

Edit: found it (or at least one) "MACH.2 is the world’s first multi-actuator hard drive technology, containing two independent actuators that transfer data concurrently."

World's first my ass. Seagate should know better, since it was them who acquired Connor Peripherals some thirty years ago. Connor's "Chinook" drives had two independent arms. https://en.wikipedia.org/wiki/Conner_Peripherals#/media/File...

Those HDDs, if single-actuator, spend around 2~4 MB of streaming potential per seek.

That means, if you access files of exactly that size you'd "only" half your iops.

HDDs are quite fine for data chunks in the megabytes.