Carousel memory
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Carousel memory is a type of secondary storage for computers, which was created by Swedish computer engineers Erik Stemme and Gunnar Stenudd.[1] It was first shown at an exhibition in Paris in 1958.[2]
Facit ECM 64 description
The FACIT ECM 64, manufactured by Swedish company Facit AB, employs a similar technique to avoid the use of a single, long magnetic tape. Instead, it has 64 small rolls with 9 meters each, with 1.6 cm wide tape on each roll, divided into 8 channels per roll.[3] The tape speed is 5 m/s.[3] To read a specific roll, the carousel rotates so the desired roll ends up at the bottom. A counter weight at the free end of the tape facilitates moving the roll out and down, into a mechanism with a read and write head. The tape is the rewound. The average seek time is 2 seconds,[3] and the storage space is 2560 kilobytes.[4] The control system is operated by transistor technology. Both the carousel and individual spools are replacable.[1]
The magnetic tape is 5/8 inch (1.6 cm) wide, 0.05 mm thick Mylar 3M Co type 188.[3] The storage density is specified to 8 bits/mm,[3] and the access head is capable of simultaneous read/write operations.[3] The power requirement is 3-phase 380 volt 50 Hz, and it needs 300 W in standby and 750 W when active. Signaling for data uses 8 parallel -20 V to 0 V 5 µs pulses.[3]
Peak transfer speed is 182,044 bits/s[3][4] using 8-parallel lines[3] and thus 22,756 bits/s per line.
The first delivery of the Facit EDB 3 computer in 1958 (to ASEA in Västerås) used the carousel memory Facit ECM 64.[5]
See also
- Karlqvist gap, calculation of magnetic field in ferromagnetic layer
- Exatron Stringy Floppy, 1978 endless tape drive 64 kB
- ZX Microdrive, 1983 endless tape drive 85 - 100 kB
- Rotronics Wafadrive, 1984 endless tape drive 128 kB
Further reading
- tekniskamuseet.se: Startsida > Veta mer > Kommunikation & IT > Datorn > Arkivmaterial (Swedish, 2009-12-02)
- tekniskamuseet.se: TPU 610301 FACIT ECM 64 Karusellminne, Preliminär teknisk beskrivning (Swedish 1961, 2012-06-15, 2936 kB)
- tekniskamuseet.se: Facit Electronic presenterar FACIT ECM 64 Magnetbandsminne av karuselltyp med direkt access (Swedish 1963, 2012-06-15, 2581 kB)
- tekniskamuseet.se: Facit electronics AB TPU 610301 (Swedish, 2012-06-15, 1702 kB)
- tekniskamuseet.se: Facit electronics AB TPU 610301 Facit ECM 64 Karusellminne, Preliminär teknisk beskrivning (Swedish, 2012-06-15, 3858 kB)
- tekniskamuseet.se: Facit electronics AB, Photographs Facit ECM 64 (Swedish, 2012-06-15, 2618 kB)
- utah.edu: Nordisk tidskrift for informationsbehandling Volume 2, Number 1, March, 1962
- springer.com: Applications to the magnetic tape storage unit, facit ECM64 (the Carousel Memory), BIT Numerical Mathematics, March 1962, Volume 2, Issue 1, pp 16–20 (article)
References
- ↑ 1.0 1.1 Lua error in package.lua at line 80: module 'strict' not found. (HTML 26 kB)
- ↑ Lua error in package.lua at line 80: module 'strict' not found. (HTML 67 kB)
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 Lua error in package.lua at line 80: module 'strict' not found. (2936 kB)
- ↑ 4.0 4.1 Lua error in package.lua at line 80: module 'strict' not found. (2581 kB)
- ↑ Lua error in package.lua at line 80: module 'strict' not found. (682 kB)
