Attack of the clones could describe Caelus Memories’ plug compatible  drive  that was built with the encouragement of IBM by ex-RAMAC employees in San Jose.  The actuator bears a strong resemblance to the RAMAC 305 but with a fixed horizontal movement.

A facility was purpose-built in 1967 a close distance from IBM’s own San Jose plant.   While Caelus got required licensing, IBM was hit in 1970 by the defection of Gene Amdahl, a company fellow who built a 370 compatible mainframe.

Drive technology changed rapidly as by 1973 the company was competing with Winchester drives and the floppy disk.  Even the Greek god of invention was no match for obsolescence.  The site where the factory once stood is now a medical test lab.