Research Of The HDD Spiral Servo Technology And Servo Pattern Generator

Disk without servo information can not be accessed. After writing servo signal on disk, the magnetic head can locate the desired position according to the servo signal. There is a desire to obtain ever increasing storage capacity on disc drives. There is also a desire to reduce the size of disc drives. One of the ways in which both of these objectives are accomplished is to increase the number of TPI (Track Per Inch) on the disc surface. But the time taken for writing servo information to the disk also increases greatly with the increasing of TPI. Furthermore, the traditional servo track writer should be used in clean room. But the maintenance of the clean room costs very much. So there is a need to design a new kind of servo writing method to reduce the time in the clean room.With the increasing of the TPI, much amount of corresponding servo writers are needed, which greatly increases the production cost of hard disk drives. So, there is also a need to design a new kind of servo track writer wich can be easily updated without replacing the main equipment of it.This paper proposes a new kind of spiral servo track format. The main method is that two same burst signals are writen at junctions of spiral servo tracks and desired tracks, which provide exact position error signal. By this method, it can greatly enhance the position resolution, increase the quality of production servo signal, reduce the swing of read/write head, reduce the exhaust of energy, and increase the TPI.Finally, a servo pattern generator based on ARM2410S is designed by the means of modularization with a high-powered CPLD, and its wave emulator is provided.