FUJITSU MAV2036RC - Manual (Page 21)

1.1 Standard Features
C141-E219 1-5
(20) Microcode downloading
The HDD implements the microcode download feature. This feature achieves easy maintainability of
the HDD and function enhancing.
1.2 Hardware
Structure
The HDD is composed of the disks, heads, and spindle motor mounted disk enclosure (DE) with
actuator as well as read/write pre-amp with the printed circuit assembly (PCA) of the controller.
(1) Disks
The disks have an outer diameter of 65 mm (2.56 inch).
(2) Heads
The heads have MR (Magnet-Resistive) read element Ramp Load type slider.
(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 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 are controlled and positioned via feedback servo loop.
The heads are positioned on the ramp when the power is off or the spindle motor is stopped.
(5) 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.
(6) 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 SAS controller.