JPS6479904A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To read and write data under a constantly optimum condition corresponding to the characteristic fluctuation of a magnetic head or a magnetic disk by switching the quantity of correcting a writing timing corresponding to an identifying resistance in a head disk assembly. CONSTITUTION:The resistance value of the identifying resistor R1 of the head disk assembly HDA 10 is set according to the characteristic of the magnetic head and the magnetic disk. Then, in order to detect the resistance value of the resistor R1, a detecting circuit 20 compares a resistance voltage set in resistances R22-R24 with the voltage of an HDA identifying signal 102 obtained according to the potential dividing ratio of the resistances R1 and R21 in voltage comparators 25, 26. The output and control signal 103 of a comparing result controls the selector 33 of a writing circuit 3 to switch the quantity of correcting the writing timing. Then, the selector 33 selects the quantity for correcting the optimum writing timing from the signal 103 from the detecting circuit 20 and outputs to a driver 34. Then, the driver 34 converts to a level suitable for driving the magnetic head in the HDA 10 to output to the HDA 10.