The 1301 reduced the average read head-to-surface distance of from 1,000 micro inches in the RAMAC to 250 micro inches. A micro inch is one-millionth of an inch. To put that into perspective, a human hair is 2,000 micro inches thick. Today's hard drive heads fly about 10 nanometers off the platter, far narrower than line widths used in semiconductor technology.

The success of a disk drive "is derived from a mechanical feature," said Hoagland. "By reducing the [read/write head-to-platter] separation, you're constantly scaling the dimensions for higher densities."

Only two years after creating the 1301, IBM built the first removable hard drive, the 1311. The drive system, which shrunk storage technology from the size of a refrigerator to the size of a washing machine, had six 14-inch platters and contained a removable disk pack that had a maximum capacity of 2.6MB of data. The 1311 remained in use through the mid-1970s.

In 1979, Al Shugart, who had helped develop the RAMAC with IBM, launched Seagate Technology Corp., which became the largest disk drive manufacturer in the world.