IBM 305 RAMAC
The IBM 305 RAMAC (short for r andom- a ccess m ethod of a ccounting and c ontrol) was the first commercially successful computer that a hard drive disposal. It could accommodate up to two 350 Disk Storage Unit hard drives and store data in real time .
The hard disk had a capacity of 5 million 7-bit characters (corresponds to 4.375 million octets , i.e. 4.375 megabytes in today's parlance). It weighed one ton and was 60 × 68 × 25 inches (152.4 × 172.72 × 63.5 cm) in size . The data were stored on 50 plates coated with iron oxide . The storage capacity was divided into 50,000 blocks of 100 alphanumeric characters each. At a rotation speed of 1200 revolutions per minute, up to 100 bits per inch were saved and an access time of 600 milliseconds was achieved. Another model of the hard drive had 10 million characters of storage capacity.
The computer was announced by IBM in May 1955 and was first presented to the public on September 14, 1956. It was produced from 1956 to 1961. More than 1000 of the computing systems with vacuum tubes were produced and from 1957 to 3200 each US dollar rented monthly. IBM provided a 305 RAMAC free of charge to the 1960 Winter Olympics . In 1969, the 305 RAMACs were withdrawn from IBM.
A chess program of considerable skill could be run on the computer . In April 1960, the Italian IM Mario Monticelli lost a game of chess against an IBM 305 RAMAC at the Fiera Campionaria exhibition center in Milan .
IBM 305 RAMAC
One of the 50 24-inch storage disks
Disk stack of the hard disk (air flow indicated)
Web links
- snopes.com: Computer Storage (1956)
- IBM Archives: IBM 305 RAMAC
- Adolivio Capece: "Secret grandfather" discovered by Deep Blue? ChessBase , Chess News, March 3, 2021
supporting documents
- ↑ IBM Archives> Exhibits> History of IBM> 1960s
- ^ Computer To Score Olympics , Medford Mail Tribune (Medford, Oregon), Jan. 11, 1959, p. 11
- ^ Corriere milanese, Cervello elettronico gioca agli scacchi contro un campione , Giovedi - Venerdi, 21-22 April 1960