The cartridge permitted users to have relatively unlimited off-line storage and to have very fast access to such data.
Although the 14-inch cartridge could not fit in a shirt pocket, unlike DECtape, the RK05 provided personal, portable, and expandable storage.
The cartridge contained a single, 14" aluminum platter coated with iron oxide in an epoxy binder.
They were positioned by a voice coil actuator using a linear optical encoder for feedback.
Discrete electronics computed the velocity profile for seeks commanded by the controller.
When used on 12-bit systems such as the PDP-8, the drive stored 1.6 megawords (so roughly the same bit capacity, albeit formatted differently).