The model 2351A incorporated eleven platters rotating at 3,960 rpm, taking half a minute to spin up. The Eagle used platters, unlike most of its competitors, which still used the standard set in 1962 by the IBM 1311. One moving head accessed each data surface (20 total), one more head was dedicated to the servo mechanism. The model 2351AF added 60 fixed heads (20 surfaces × 3 cylinders) for access to a separate area of 1.7 MB.
