Early-to-mid 1960s. Foreground: IBM 2311 Disk Storage Drives, providing random direct access to 7.25 million 8-bit bytes per removeable disk pack. In Packed Decimal Mode the capacity is 14.5 numeric characters. Eight drives can be attached to a single control unit for a total of 58MB or 116 million digits.
Transfer rate: 156,000 bytes per second (alphanumeric). Average seek time: 85 milliseconds Track-to-track access time: 30 milliseconds Recording tracks: 2000 Cylinders: 200
Not shown is the IBM 2314 Direct Access Storage Facility, a newer model disk drive with a capacity of 25.87MB, nearly four times the 2311, and double the transfer rate (312,000 bytes/sec).
Background: IBM 2400 9-track 800bpi tape drives. This was IBM's first 9-track model, and therefore the first model capable of recording EBCDIC (8-bit) or ASCII (7-bit) information; earlier drives were 7-track and could record only BCD (a 6-bit character set composed of digits, uppercase Roman letters, and a handful of symbols). And between the two figures, an IBM 2301 Drum Storage Unit (thanks to Ralph Brandt for noticing it). On the right, an IBM 360 Model 75 control panel (like the one in our own machine room).
Center: Operator devices including an IBM 1052 Console Typewriter.
Photo: IBM [32].
Last Update: Fri Jul 11 15:19:39 2008