Fujitsu MBA3073NP Manual Do Utilizador

Página de 138
1.2 Hardware 
Structure 
 
The HDDs have a disk enclosure (DE) and a printed circuit board assembly (PCBA).  The DE 
includes the heads on an actuator and the disks on a spindle motor mounted on the DE.  The 
PCBA includes a read/write circuit and a controller circuit. 
(1) Disks 
 
The disks have an outer diameter of 70 mm (2.8 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 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 are controlled and positioned via feedback of 
servo information in the data. 
 
The heads are positioned on the ramp 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 MEEPRML (Modified Enhanced Extended Partial Response 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. 
 
18 
C141-E270