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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
Zone
0
Cylinder
0
to
1230
Transfer rate
40.69
[MB/s]
Zone
8
Cylinder
9531
to
10870
Transfer rate
32.29
[MB/s]
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.
4 - 12
Write clock frequency and transfer rate of each zone
1
2
3
1231
2561
3821
to
to
to
2560
3820
5610
40.69
39.67
38.08
9
10
11
10871
11531
12201
to
to
to
11530
12200
13300
31.42
30.58
29.10
C141-E090-01EN
4
5
6
5611
6511
6941
to
to
to
6510
6940
8640
37.21
36.78
34.90
12
13
14
13301
14031
15161
to
to
to
14030
15160
15870
28.09
26.49
24.54
7
8641
to
9530
33.89
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