JPS6442060A - Magnetic disk device system - Google Patents

Abstract

PURPOSE:To correct skewing with small capacity of data buffer by controlling the rotational period and the rotational angular phase of each of the disk rotation drive motors of plural magnetic disk devices operated concurrently so that they are synchronized with a periodical signal which is made a common reference. CONSTITUTION:The titled device is provided with a second comparator 11 that compares the phase (and frequency) of a reference index clock 5A having the same period as target disk rotational period generated by a second reference device 10 with that (and frequency) of an index clock 5 obtained from a clock discrimination circuit 4. And an output from the second comparator which is the phase difference (and the frequency difference) between said two input signals, is inputted to an adder-subtracter 12 as a correction value for an output from a first comparator 8, and the arithmetic result from the 12 is amplified by a drive amplifier 9 to drive a spindle motor 1. Accordingly, the rotational angular phase of a disk is controlled to be the state locked with the phase of the reference index 5A. As a result, the data buffer for the correction of timing skew can be reduced, and the titled system can be obtained with comparatively simple circuit.