The M2301 magnetic disk unit was the first magnetic disk unit from Fujitsu to use 8-inch, small diameter media. It was completed in June 1979. Fujitsu's 8-inch disk units were called the Swallow Series, and starting with the second generation Swallow-2 in 1981, Fujitsu moved in earnest into the OEM market for 8-inch disks. The later Swallow Series maintained its original physical dimensions, but continued to increase its memory capacity, roughly doubling every two years. The Swallow-6 (completed in 1989) had a 2Gbyte memory capacity—24 times the 84MB of the Swallow-2, which was completed in 1981. Fujitsu lead the 8-inch disk market with the Swallow Series, and the external dimensions and mounting dimensions of the Swallow disk became the international standard.
The aforementioned increase in memory capacity was achieved using the following technologies:
- 1) Recording density was improved by using state-of-the-art access head and disk media technology.
- 2) Track density was improved by using an advanced actuator structure to control off-tracking. (Swallow-2 and later)
- 3) High reliability was achieved by raising airtightness with a disk enclosure structure. (Swallow-2 and later)
As 5.25-inch disk units improved in performance and capacity, the market for 8-inch disk units shrunk, and Fujitsu's final product for OEM was the M2671P (Swallow-7) completed in 1991.
|Completion date||June 1979||April 1981||November 1983|
|Average positioning time||70ms||20ms|
|Disk rotation speed||2,964rpm||3,600rpm|
|Average rotational delay||10.1ms||8.3ms|
|Data transfer speed||1.229Mbyte/s|
|Completion date||November 1984||June 1987||April 1989|
|Average Positioning time||20ms||16ms||12ms|
|Disk rotation speed||3,600rpm|
|Average rotational delay||8.3ms|
|Data transfer speed||2.458Mbyte/s||3.0Mbyte/s|
*1: Using M1053 controller