Abstract
PROBLEM TO BE SOLVED: To improve a method and a device for correcting the RRO of a data storage device. <P>SOLUTION: The method for reducing the RRO errors includes the step of obtaining an RRO measured value for each track, the step of calculating the discrete Fourier conversion (EFT) for each RRO measured value to characterize the RRO measured value for each track by using real and false numerical values, and the step of executing minimum square conformance for all the real numerical values to specify the first group (n+1) coefficient of an n-order polynomial function which is the function of a track (r) and represented by Ai(r)=anrn+a(n-1)r(n-1)+... +a1r+a0. Further, the method includes the step of executing minimum square conformance for all the false numerical values to specify the second group (n+1) coefficient of an n-order polynomial function which is the function of a track (r) and represented by Bi(r)=bnrn+b(n-1)r(n-1)+... +b1r+b0. RRO correction is executed based on DRRO(r, s)=ΣiforallHäAi(r)cos(i(s2π/total_sectors))+Bi(r)sin(i(s2π/total_sectors))}.