This magnetic drum was commercialized in 1970 as a magnetic drum unit for the HITAC-8000 Series. This was done by reducing size and increasing capacity of the previously commercialized H-8566 magnetic drum with floating head system.
Volume was reduced to about 1/4 the previous volume by, for example, reducing diameter of the rotor from the previous 360mm to 250mm, and adopting a built-in drive motor. An increase in capacity to 4MB (megabytes)-twice the previous capacity-was achieved by, among other things, reducing spacing between the floating magnetic head and media on the rotor surface, and using the FM recording system. Average access time was 10.3ms, as before.
The magnetic drum used in the H-8567 magnetic drum unit was commercialized as a standalone drum with the model name FV-2450, and was also marketed for use in digital switching systems and by other companies in the same industry. The FV-2540 magnetic drum was a product developed through joint research by Nippon Telegraph and Telephone Public Corporation and Hitachi, Ltd.
| Unit model name | H-8567-1/-2 | |
|---|---|---|
| Completion date | 1970 | |
| Head type | Floating head | |
| Head floating distance | 1.7 μm | |
| Memory capacity | 4 MB | |
| Recording system | FM recording system | |
| Average access time | 10.3 ms | |
| Data transfer speed | -1 type:2.2 Mbit/s(serial transfer) -2 type:8.8 Mbit/s(4 bit parallel transfer) |
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| Drum | Name of unit used | FV-2540 |
| Number of tracks | 856 | |
| Rotation speed | 3,000 rpm | |
| Rotor dimensions | 250 ø×420 mm | |
| Recording density | 56 bit/mm | |
| Connected systems | Digital switching systems/DIPS/ Subscriber data communication systems Seat reservation systems HITAC-8000 Series |
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