M40S 9
SAMSUNG HARD DISK DRIVE
put power on and no matter what HDD read or write data,spindle motor always revolve.
Besides accurate reading from the media point of view is possible when maintain the constant
speed within 0.1%,rotation error. The control circuit of spindle motor receive the index data
from the spindle motor or media at every spin and check whether constant speed persists or not
then revise the speed. Spindle motor is applied to DC brushless motor.
12 Actuator
Hard disk has 2 disks so it has 4 written sides, and each side needs each written replay
device, 8 heads needed. This 4 heads can't work independently. Each head is connected with
one carriage and set as running altogether. For example, one head move at tenth track and
then the rest come to move at the same track. Retrieval(information searching) is a moving
the head to track properly. The faster searching speed, the better for a quick access.
It is profitable to use voice coil motor for a fast searching speed. Making narrow
the width and interval of track is for HDD capacity improvement so we can build more tracks
on written side so searching movements in head become subtle. Therefore servo control the
decision of HDD location. Magnetic disk is put standard signal for location marking from the
manufacturing step. Head read this to find the relative difference then run motor mediate
the head's location.
13 Magnetic Head
Magnetic field is formed around the conduct on passing electric current to conductor and
the direction and size of magnetic field are decided by those of an electric current.
Magnetic head build a minute gap in core (formed by ring) and pass an electric current then
strong magnetic leakage are occurred around gap thus magnetic particles of media vary the
direction according to the that of current: this is called recording. On the contrary, a
process induce magnetic signal to electric signal is called reading(decipherment).
14. Magnetic Disk
Recording carrier become a permanent magnet according to applying magnetic material to the
surface and change the magnetization direction of a electromagnet and it is possible to
store information during long term.
15. PCBA
PCBA is a circuit element concerning about HDD running and constructed in
engine IC,COMBO IC,read/write IC,ROM ,and sort of chip etc.
- Engine IC: contained RAM&Interface IC and exchange information to computer.
- COMBO IC: Controlling spindle motor & VCM running when HDD power on.
- Read/Write IC: read/write of HDD
- ROM: Checking HDD basic function and management basic spec.
16. Ramp
2.5 inch drives usually adopt Load /Unload ramp system to prevent head slap for disk basically.
Head is putted safely on the ramp which is located off disk-outer diameter at non-operating
It makes head avoid to slap disk during the external shock. and play a major role to move to
disk smoothly at loading and move smoothly and safely to itself to park head at power-off.