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IBM Receives the Fundamental Patent for Disk Drives

1964 to 3/24/1970
IBM 305 RAMAC. Photo by U. S. Army Red River Arsenal.


IBM 305 RAMAC. Photo by U. S. Army Red River Arsenal.


On March 24, 1970 IBM received US Patent 3,503,060, the fundamental patent for disk drives.

"The invention of the hard disk drive was clearly led and inspired by Rey Johnson, the IBM San Jose Laboratory Director, with the day to day management of the project led by Lou Stevens beginning November 1, 1953. However, 5,600 miles away and more or less simultaneously, a prolific German inventor Gerhard Dirks was inventing the same thing.

"During World War II, Dirks as a Russian prisoner of war in occupied Germany was incarcerated for several years in a building containing a technical library. Dirks, with little else to do, spent his time reading and studying in the library during which he conceived versions of magnetic drum and core storage. When the war ended, he returned to his former employer, the Krupp Company, but failed to interest it in taking a license to his German patent application. A small German company, Siemag Fein Mechanische Werke GmbH, that manufactured bookkeeping machines did show interest and, in return for an exclusive German license, paid Dirks a modest sum, enough to enable him to file his patent application worldwide.

"On December 14, 1954 Lou Stevens, Ray Bowdle, Jim Davis, Dave Kean, Bill Goddard and John Lynott of IBM San Jose filed a US Patent application as the co-inventors of the several potential inventions disclosed therein. Because under US law a patent can claim only one invention in 1962 the application was split into two applications, one relating the the RAMAC 305 System itself and one relating to a Magnetic Transducer Mounting Apparatus. The two applications were identical as to disclosure and drawings and when issued were substantially identical differing only in the claimed invention.
  • US Patent 3,134,097 was the first to issue on May 19, 1964; invented by Stevens, Goddard & Lynott it claimed the 305 RAMAC system.
  • US Patent 3,503,060 issued March 24, 1970; invented by Goddard & Lynott, it claimed both a Magnetic Transducer Mounting Apparatus and Disk Drives in general.
"The broad claims on Disk Drives were not originally in the IBM application that became the '060 patent but were added by IBM during the application's review by the US Patent Office" (, accessed 10-22-2013).

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