The IBM 305 RAMAC was the first commercial computer that used a moving-head hard disk drive for secondary storage. The system was publicly announced on September 14, 1956, with test units already installed at the U.S. Navy and at private corporations. RAMAC stood for "Random Access Method of Accounting and Control", as its design was motivated by the need for real-time accounting in business. The first RAMAC to be used in the U.S. auto industry was installed at Chrysler's MOPAR Division in 1957. It weighed over a ton. The IBM 350 disk system stored 5 million alphanumeric characters recorded as 6 data bits, 1 parity bit and one space bit for 8 bits recorded per character. The original 305 RAMAC computer system could be housed in a room of about 9 m by 15 m; the 350 disk storage unit measured around 1.5 square metres. Programming the 305 involved not only writing machine language instructions to be stored on the drum memory, but also almost every unit in the system could be programmed by inserting wire jumpers into a plugboard control panel...
