Fujitsu MAT3147NC/NP, MAT3300NC/NP, MAT3073NC/NP manual

(1)Disks

The disks have an outer diameter of 84 mm (3.3 inch) and an inner diameter of 25 mm (0.98 inch). The disks are good for at least 50,000 contact starts and stops.

(2)Heads

The MR (Magnet - Resistive) of the CSS (contact start/stop) type heads are in contact with the disks when the disks are not rotating, and automatically float when the rotation is started.

(3)Spindle motor

The disks are rotated by a direct-drive hall-less DC motor. The motor speed is controlled by a feedback circuit using the counter electromotive current to precisely maintain of the specified speed.

(4)Actuator

The actuator, which uses a rotary voice coil motor (VCM), consumes little power and generates little heat. The heads at the end of the actuator arm is controlled and positioned via feedback of servo information in the data.

The heads are positioned on the CCS zone over the disks when the power is off or the spindle motor is stopped.

(5)Air circulation (recirculation filter, breather filter)

The disk enclosure (DE) configures a clean room to keep out particle and other contaminants. The DE has a closed-loop air recirculation system. Using the movement of the rotating disks, air is continuously cycled through a filter. This filter will trap any particle floating inside the enclosure and keep the air inside the DE contaminant free. To prevent negative pressure in the vicinity of the spindle when the disks begin rotating, a breather filter is attached. The breather filter also equalizes the internal air pressure with the atmospheric pressure due to surrounding temperature changes.

(6)Read/write circuit

The read/write circuit utilizes a read channel mounted with a head IC that supports high-speed transmission and an MEEPR4ML (Modified Enhanced Extended Partial Response Class 4 Maximum Likelihood) modulation/demodulation circuit in order to prevent errors being triggered by external noise and to improve data reliability.

(7)Controller circuit

The controller circuit uses LSIs to increase the reliability and uses a high speed microprocessing unit (MPU) to increase the performance of the SCSI controller.

C141-E201 1-7