IBM RAMAC 305 Introduced in 1956, the IBM 305 RAMAC (Random Access Method of Accounting and Control) was an electronic general-purpose data processing machine that maintained business records on a real-time basis. The 305 RAMAC was one of the last vacuum tube systems designed by IBM, and more than 1,000 of them were built before production ended in 1961. The system took up the better part of an entire room and required three administrators to run it.