Every time you access your computer’s hard drive, you’re tapping into the innovative work of Jake Hagopian ’39.
As an advisory engineer in IBM’s Research Laboratory in San Jose, Calif., Jacob J. Hagopian perfected the spin-coating method for making computer disks, which revolutionized both how and how quickly files were read from magnetic media.
In 1953, work began at IBM on RAMAC (Random Access Method of Accounting and Control), the first computer with a disk drive. The drive, or disk file, as it was called, contained 50 disks stacked one-quarter inch apart, on a rotating, vertical shaft. A single pair of magnetic heads moved in between the disks to read or write the tracks. To move to another disk, the arm containing the heads had to pull out completely and then travel up or down. Designers solved the problem of maintaining constant spacing between the magnetic head and the slightly fluttering disks, but Hagopian noticed two problems with their method. First, a bulky air compressor was needed to supply the large volume of air required to “float” the heads and keep them from crashing into the disks. Second, with just two read-write heads, scanning an entire file was an extremely slow process (it took about eight minutes to search through all 50 disks).
Jacob Hagopian’s work on a method for coating magnetic disks is detailed on a page taken from his IBM journal, an item that is part of the Hagopian papers held in Special Collections in WPI’s George C. Gordon Library.
Flying heads, spinning disks
Hagopian reasoned that if the heads could be made to float without the use of air compressors, 100 heads could be ganged to scan each of the disk surfaces simultaneously. “I recognized that the rotation of the disk pulled along air molecules, creating its own pressure layer without the need for air supply,” he explained in an IBM report on the project. “This simple but very important effect is fundamental to slider air-bearing design principles.” He created an elementary form of the “flying” head by placing the taper-flat, polished face of a circular aluminum capsule down on a rotating magnetic disk; the capsule floated on a self-generated film of air. “I was elated by the flying head and what it could do,” he said. “I immediately submitted a patent disclosure describing the two basic air-bearing surface shapes needed for stable operation.”
Before the RAMAC could become a commercial product, another problem had to be solved: how to apply the magnetic coating to the disks. “We tried dipping, spraying, and silk-screening techniques to apply the magnetic ink to the disk,” Hagopian said, “but none gave a smooth, uniformly thin coating.” So he took his work home. According to his daughter, Anita, he used one of his wife’s stockings and the family’s record player to control the flow of paint as it poured onto a record turning at 75 rpm, using centrifugal force to evenly coat the album. This spin-coating method was later patented—one of 24 patents under Hagopian’s firstname.lastname@example.org
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Last modified: Dec 16, 2004, 14:15 EST