Storage device for reliably maintaining data in a reproducible state for a long period of time

Abstract

A time counting device, a cache memory and a copy control circuit are added to a conventional disk drive so that recorded information is copied periodically and automatically. Alternatively, a cache memory, a copy control circuit, a reference control circuit, a first time counting device and a second time counting device are added to the conventional disk drive so that information which remains recorded for a predetermined period of time after its last recording date is automatically copied. According to another embodiment, a reference signal is recorded in advance and a reproduced output is periodically measured. If the reproduced output is lower than a reference value, recorded information is automatically copied. Other embodiments are also disclosed with the aim of ensuring that information recorded on a magnetic media can always be reproduced reliably, even in the case of high density recording.

Dependencies are inferred from the claim text.