Perhaps another option is to go back to the 1980's hdd designs where the arm moves straight down the radius of the platter. This design might permit multiple he

Perhaps another option is to go back to the 1980's hdd designs where the arm moves straight down the radius of the platter. This design might permit multiple heads on the same arm. At my first job, sysadmin and programming on a PDP-11/44, 1-2 fascinating Winchester drives were procured for it. They had clear plastic covers, and you could see everything, the disk, the actuator, which had two heads, and it was by and large square, I'm almost positive it was rotary, not solenoid based straight stroke like many '70-80s drives, CDC's famous line in particular.