Abstract: A steam generator with improved safety and ease of use is provided. In this steam generator, water provided from a water tank is heated by a heater to generate a steam in a chamber, and then the steam is sprayed out through a steam channel. An overflow port is formed in the water tank such that an adequate water level is safely maintained even when an excessive amount of water is supplied into the water tank from a water inlet. The steam generator has a shutter disposed in a drain channel for water drained from the water tank through the overflow port and an interlocking mechanism for opening and closing the shutter in response to an opening and closing motion of a cover for the water inlet. This achieves good usability of the steam generator.

Abstract: A tape cassette of this invention is equipped with a memory capable of accommodating management information. The memory retains an MIC logical format type designating a format state, either formatted or unformatted, of the magnetic tape. A check is made on the consistency between the format state designated by the MIC logical format type and the format state estimated by reading data from the magnetic tape. If an inconsistency is detected, that is interpreted to mean that the tape cassette has been tampered with, and read and write operations on the cassette are controlled accordingly. This enhances security against fraudulent uses of a tape drive system loaded with the tape cassette.