JPS6414779A - Storage device - Google Patents

Abstract

PURPOSE:To prevent information from being erased by detecting the existence of a positioning error when the amplifying gain of a speed demodulator is different from rated gain to detect that the variable range of the amplifying gain detecting no positioning error goes to narrower then a prescribed range. CONSTITUTION:A positioning margin detecting circuit 21 connected to the speed modulator 16A whose amplifying gain is to be varied varies the amplifying gain of the speed modulator 16A on the basis of an instruction from an electronic computer 19, detects that the variable range of the amplifying gain detecting no positioning error goes to narrower than the prescribed range based on an error detecting signal C from an error detecting circuit 20 and outputs an abnormality detecting signal D. Then, the increment of frictional resistance between a head 4 and a recording medium 3 due to a flaw on the head 4 or the medium 3 is decided and information is reproduced from the medium 3 based on a command from the computer 19 before the head 4 falls on the medium 3 and stored in another recording medium. Consequently, the recording medium 3 can be previously prevented from generating an information erasing accident.