FUJITSU MPE3XXXAE - Manual (Page 57)

C141-E093-01EN 4 - 12
4.6.4 Synthesizer circuit
The drive uses constant density recording to increase total capacity. This is different from the
conventional method of recording data with a fixed data transfer rate at all data area. In the
constant density recording method, data area is divided into zones by radius and the data
transfer rate is set so that the recording density of the inner cylinder of each zone is nearly
constant. The drive divides data area into 15 zones to set the data transfer rate. Table 4.2
describes the data transfer rate and recording density (BPI) of each zone.
Table 4.2 Write clock frequency and transfer rate of each zone
Zone 0 1 2 3 4 5 6 7
Cylinder 0
to
964
965
to
2150
2151
to
3580
3581
to
4790
4791
to
6120
6121
to
8030
8031
to
9440
9441
to
11210
Transfer rate
[MB/s]
34.44 34.44 34.44 34.44 33.41 31.83 30.59 28.71
Zone 8 9 10 11 12 13 14
Cylinder 11211
to
12170
12171
to
12590
12591
to
13430
13431
to
14430
14431
to
15860
15861
to
16660
16661
to
17300
Transfer rate
[MB/s]
27.68 27.14 26.10 24.80 22.96 21.93 20.36
The MPU transfers the data transfer rate setup data to the RDC that includes synthesizer circuit
to change the data transfer rate.
4.7 Servo Control
The actuator motor and the spindle motor are submitted to servo control. The actuator motor
is controlled for moving and positioning the head to the track containing the desired data. To
turn the disk at a constant velocity, the actuator motor is controlled according to the servo data
that is written on the data side beforehand.