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IBM drum storage
In early computers drum storage consisted of a large metal cylinder, coated on the outside surface with a ferromagnetic recording material. Drums were later largely replaced by the hard disk drive.
Drums were used as main memory by IBM in computers including the IBM 305 and IBM 650; IBM also offered drum devices as secondary storage for the 700/7000 series and System/360 series of computers.
The IBM 731 is a discontinued storage unit used on the IBM 701. It has a storage capacity of 2,048 36-bit words (9,216 8-bit bytes).
The IBM 732 is a discontinued storage unit used on the IBM 702. It has a storage capacity of 60,000 6-bit characters (45,000 8-bit bytes).
The IBM 733 is a discontinued storage unit used on the IBM 704 and IBM 709. It has a storage capacity of 8192 36-bit words (36,864 8-bit bytes).
The IBM 734 is a discontinued storage unit used on the IBM 705 It has a storage capacity of 60,000 6-bit characters (45,000 8-bit bytes).
The IBM 7320 is a discontinued storage unit manufactured by IBM which was announced on December 10, 1962 for the IBM 7090 and 7094 computer systems, was retained for the earliest System/360 systems as a count key data device, and was discontinued in 1965. The 7320 is a vertically mounted head-per-track device with 449 tracks, 400 data tracks, 40 alternate tracks, and 9 clock/format tracks. The rotational speed is 3,490 rpm, so the average rotational delay is 8.6 milliseconds.
Attachment to a 709x system is through an IBM 7909 Data Channel and an IBM 7631 File Control unit, which can attach up to five random-access storage units: a mix of 7320, 1301, and 1302 DASD. One or two 7631 controllers can attach to a computer system, but the system can still attach only a total of five DASD. When used with a 709x, a track holds 2,796 6-bit characters, and a 7320 unit holds 1,118,400 characters. Data transfer rate is 202,800 characters per second.
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IBM drum storage
In early computers drum storage consisted of a large metal cylinder, coated on the outside surface with a ferromagnetic recording material. Drums were later largely replaced by the hard disk drive.
Drums were used as main memory by IBM in computers including the IBM 305 and IBM 650; IBM also offered drum devices as secondary storage for the 700/7000 series and System/360 series of computers.
The IBM 731 is a discontinued storage unit used on the IBM 701. It has a storage capacity of 2,048 36-bit words (9,216 8-bit bytes).
The IBM 732 is a discontinued storage unit used on the IBM 702. It has a storage capacity of 60,000 6-bit characters (45,000 8-bit bytes).
The IBM 733 is a discontinued storage unit used on the IBM 704 and IBM 709. It has a storage capacity of 8192 36-bit words (36,864 8-bit bytes).
The IBM 734 is a discontinued storage unit used on the IBM 705 It has a storage capacity of 60,000 6-bit characters (45,000 8-bit bytes).
The IBM 7320 is a discontinued storage unit manufactured by IBM which was announced on December 10, 1962 for the IBM 7090 and 7094 computer systems, was retained for the earliest System/360 systems as a count key data device, and was discontinued in 1965. The 7320 is a vertically mounted head-per-track device with 449 tracks, 400 data tracks, 40 alternate tracks, and 9 clock/format tracks. The rotational speed is 3,490 rpm, so the average rotational delay is 8.6 milliseconds.
Attachment to a 709x system is through an IBM 7909 Data Channel and an IBM 7631 File Control unit, which can attach up to five random-access storage units: a mix of 7320, 1301, and 1302 DASD. One or two 7631 controllers can attach to a computer system, but the system can still attach only a total of five DASD. When used with a 709x, a track holds 2,796 6-bit characters, and a 7320 unit holds 1,118,400 characters. Data transfer rate is 202,800 characters per second.