Patent ID: 6542917
Filing Date: 2003-04-01
Classification: G06F

Abstract:
A storage apparatus comprising:a seek control unit for performing a seek control by speed controlling a head; and an approximate value calculating unit for, when a square root arithmetic operation is needed in a calculation of a seek speed target value which is used in said seek control, dividing a range of an input value serving as a target of said square root arithmetic operation into a plurality of intervals, setting an approximate function for approximately outputting a square root of said input value every said interval, and selectively using an approximate function corresponding to an interval to which said input value belongs, thereby calculating a square root approximate value of said input value, wherein said approximate value calculating unit approximates a square root f(x)={square root over (x)} by a piecewise function f{circumflex over ( )}(x)=fn{circumflex over ( )}(x), knÂ·X0&lE;xn+1Â·X0 â€ƒwhere, n: integer showing an interval number k: constant X0: arbitrary value showing a basic value of an interval boundary of the input value x.