Abstract: A disk device that records information on a storage medium includes a first reading-out section that reads out defective address information in which a defective address indicative of a physical position of a defective part of the storage medium is recorded; a blocking section that, when a value of intervals between a plurality of the defective addresses in the defective address information which has been read out by the first reading-out section is less than a specific value in terms of a specific unit, sets the specific unit as a defective block; a second reading-out section that reads out data fin the defective block set by the blocking section; and a writing section that writes the data which has been read out by the second reading-out section into an area different from the defective block in the storage medium based on the specific unit.

Abstract: A set of filters are arranged in sequence for verification and analysis of digital circuit designs. The filters are either active filters, which are directly involved in verification of circuit designs (e.g., a Binary Decision Diagram (BDD)-based verifier or an automatic test pattern generation (ATPG)-based verifier), or passive filters, which gather information about the circuit or transform the circuit structure in order to simplify the verification problem (e.g., random pattern simulation or circuit partitioning). Given a pair of circuits to be verified, the filter approach first subjects the circuits to very simple, fast techniques having very low memory usage requirements. These steps are followed by a series of increasingly powerful methods that are more time consuming and often require more computer memory for their operation.