I was thinking that the controller probably takes care of interleaving data across platters, so at least small enough random I/Os would be able to use only one actuator.

I did some more reading and the PDF [1] says it shows up as two separate LUNs behind a single SAS port, but sharing the drive cache.

But what I initially didn't catch (and another comment here pointed out), is how come they claim to do over 500 MB/s of sequential scanning I/O. Small random IOPS I get, but for large sequential I/Os you still have the same amount of platters, with the same bit-density, rotating at the same speed... Or is even the sequential I/O throughput "bottleneck" mostly dominated by the tiny seeks + calibration to the next adjacent track and not the actual magnetic reading part?

I now really want to buy one for (some?) reason. Could get an used version from amazon for $150 but I'll try to hold back. It's also interesting that there are no new, unused versions available there (discontinued?)

[1] https://www.seagate.com/files/www-content/solutions/mach-2-m...