Abstract: This invention has for its object to eliminate failure of correct recording on a recording medium in an on-vehicle audio recording/reproduction device due to an instantaneous power cut-off or the like. In order to achieve this object, a file system is used for managing files hierarchically by using files having information and a directory as a storage place of a plurality of files so that predetermined information is recorded in a work sector for backup before performing the primary recording. The work sector is selected from a work sector area having a plurality of sectors and the work sector has recorded the number of mountings of the file system. Thus, an optimal work sector is used for data recovery.

Abstract: This invention has for its object to eliminate failure of correct recording on a recording medium in an on-vehicle audio recording/reproduction device due to an instantaneous power cut-off or the like. In order to achieve this object, a file system is used for managing files hierarchically by using files having information and a directory as a storage place of a plurality of files so that predetermined information is recorded in a work sector for backup before performing the primary recording. The work sector is selected from a work sector area having a plurality of sectors and the work sector has recorded the number of mountings of the file system. Thus, an optimal work sector is used for data recovery.

Abstract: A heat exchanger is provided in which high heat transfer efficiency has been attained by optimizing the slit array and setting an optimum range for the width of a slit and the spacing between slits. Slits 51 and 52 formed in front of the heat transfer coil 4 and slits 55 and 56 formed behind the heat transfer coil are arranged so as to provide a mutually different length among adjoining partitioned slits in the vertical direction, as well as a mutually different length between directly opposite partitioned slits in the horizontal direction. As a result, the position at which the slit is partitioned is staggered.

Abstract: A heat exchanger is provided in which high heat transfer efficiency has been attained by optimizing the slit array and setting an optimum range for the width of a slit and the spacing between slits. Slits 51 and 52 formed in front of the heat transfer coil 4 and slits 55 and 56 formed behind the heat transfer coil are arranged so as to provide a mutually different length among adjoining partitioned slits in the vertical direction, as well as a mutually different length between directly opposite partitioned slits in the horizontal direction. As a result, the position at which the slit is partitioned is staggered. The two slits 53 and 54 formed side by side between heat transfer coil 4 and heat transfer coil 4 are of the same length. For a 7 mm diameter heat transfer coil, the slit width relative to the diameter of the heat transfer coil ranges from 1.2/7 (approximately 0.17) to 2.0/7 (approximately 0.29), and the slit spacing relative to the diameter of the heat transfer coil ranges from 1.

Abstract: In a heat exchanger comprising a number of multilayered fins, and a refrigerant pipe arranged in the meandering form in the fins, and an air conditioner having the heat exchanger, each of the fins has a corrugated portion formed in an air-flow direction thereon, which has at least two wavelike portions for producing a turbulent flow of air having such strength that a temperature boundary layer of the air is broken, but resistance against to the air flow is not excessively high. Each wavelike portion may be designed to have a triangular section or a trapezoidal section, and a flat portion may be disposed between the wavelike portions.