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IBM RAMAC hard disk drive. Museum display of the hard disk drive and equipment used in the IBM 305 RAMAC (Random Access Method of Accounting and Control) computer. This computer was developed in the 1950s by US company IBM, and first announced in 1958. Test units had been installed in 1956 and 1957. Information was stored and retrieved on fifty discs (circular stack) that were 61 centimetres across. It was one of the earliest commercial computer hard disk drives. (KEYSTONE/SCIENCE PHOTO LIBRARY/IBM RESEARCH/SCIENCE PHOTO LIBRARY)