Samsung SP0211N Service Manual page 25

SAMSUNG HARD DISK DRIVE
⑮ Master/Slave/Cable Select: When we attached 2 IDE drive, one is master and the other is slave.
Being a M/S whether or not of drive is determined by jump in drive or cable select.
● BPI: Abbreviation of bit per inch, recording density towards a circumference. Usually we
decide the maximum diameter of track.
● Buffer: The RAM where executed data between HDD and host computer is stored in RAM
temporary.
The resolution of the bottleneck according to difference of speed and improving the efficiency.
● Controller: Same as disk controller, chip or circuit make possible transfer command and data
of computer according to HDD.
● DMA: Abbreviation of direct memory access, a technique for transferring data from main memory
to a device without passing it through the CPU. This is useful for making quick backups and
for real-time applications.
※ Servo
Local control technology enable to read and write data.When spinning flatter high-speeded
read data, head is the accurate position according to the position written data,this
technology could be a standard about HDD efficiency. Local controller apply stepping
spindle motor or voice coil motor to head located in actuator and settled a position.
More over another important factor is how far the magnetic head could fly on the surface
of hard disk. The lower the height of magnetic head is, the narrower the magnetic region
on the disk surface, so the more data can be read or written on the same disk surface.
PALO
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