Question: where is the drive store located and what 3 items does it include

title: Hard disk drive
text: In 1962 the IBM 350 RAMAC disk storage unit was superseded by the IBM 1301 disk storage unit , which consisted of 50 platters , each about 1 / 8 - inch thick and 24 inches in diameter . Whereas the IBM 350 used only two read / write heads which were pneumatically actuated and moved in two dimensions , the 1301 was one of the first disk storage units to use an array of heads , one per platter , moving as a single unit . Cylinder - mode read / write operations were supported , and the heads flew about 250 micro-inches ( about 6 μm ) above the platter surface . Motion of the head array depended upon a binary adder system of hydraulic actuators which assured repeatable positioning . The 1301 cabinet was about the size of three home refrigerators placed side by side , storing the equivalent of about 21 million eight - bit bytes . Access time was about a quarter of a second .