Carousel memory is a type of secondary storage for computers, which was created by Swedish computer engineers Шаблон:Ill and Gunnar Stenudd.[1] It was first shown at an exhibition in Paris in 1958.[2]
The FACIT ECM 64, manufactured by Swedish company Facit AB, is a prototype of carousel memory. To avoid having a single, long magnetic tape, it instead has 64 small rolls of Шаблон:Nowrap each, with Шаблон:Nowrap wide tape on each roll, divided into Шаблон:Nowrap per roll.[3]Шаблон:Rp The tape speed is Шаблон:Nowrap.[3]Шаблон:Rp To read a particular roll, the carousel rotates so the desired roll ends up at the bottom. A counterweight sits at the free end of the tape, and facilitates the roll in moving out and down into a mechanism with a read-and-write head. The tape is then rewound. The average seek time is Шаблон:Nowrap[3]Шаблон:Rp and the storage space is Шаблон:Nowrap.[4] The control system is operated by transistors. Both the carousel and individual spools are replaceable.[1]
The magnetic tape is a 5/8-inch (1.6 cm) wide and 0.05 mm thick Mylar 3M Co type 188.[3]Шаблон:RpThe storage density is specified to Шаблон:Nowrap,[3]Шаблон:Rp and the access head is capable of simultaneous read/write operations.[3]Шаблон:Rp The power requirement is 3-phase 380 volts 50 Hz with Шаблон:Nowrap when in standby and Шаблон:Nowrap when active. Signaling for data uses Шаблон:Nowrap -20 V to 0 V 5 µs pulses.[3]Шаблон:Rp
