Abstract: In acquiring a snapshot, when data in a P-VOL is updated, it is determined whether the same data as target data to be stored in a certain second storage area specified by a certain second address of a D-VOL is already stored in a different second storage area specified by a different second address of the D-VOL, the target data being the differential data generated by the update. When the same data as the target data is stored, the target data is not newly stored in the D-VOL, and the different second address, specifying the different second storage area where the same data is stored, is registered in a snapshot management table (CoW table), in association with a certain first address specifying a certain first storage area where the data from which the target data has been generated is stored.

Abstract: The file synchronization processing among sites which can reduce the response time is realized. By the CAS device creating a list of at least a part of the file groups which the first sub-computer system archived or backed up to the data center as an update list and transferring the update list to the second sub-computer system, the second sub-computer system determines whether the file is valid or not by using the update list (See FIG. 2).

Abstract: In order to provide HSM that can effectively use the storage capacity of an upper Tier in an HSM system, a lower Tier of the HSM system detects a group of files having the same data content from a plurality of files stored in the lower Tier, and keeps at least one of the real data of the group of files having the same data content while deleting the rest of the data. The upper Tier receives the process result from the lower Tier. Then, in response to a read request from the host computer that specifies a file included in the group of files and transferred to the upper Tier from the lower Tier, the upper Tier identifies the at least one of the data that is kept and corresponding to the specified file, and responds to the host computer.

Abstract: In order to provide HSM that can effectively use the storage capacity of an upper Tier in an HSM system, a lower Tier of the HSM system detects a group of files having the same data content from a plurality of files stored in the lower Tier, and keeps at least one of the real data of the group of files having the same data content while deleting the rest of the data. The upper Tier receives the process result from the lower Tier. Then, in response to a read request from the host computer that specifies a file included in the group of files and transferred to the upper Tier from the lower Tier, the upper Tier identifies the at least one of the data that is kept and corresponding to the specified file, and responds to the host computer.

Abstract: Time required for a file server to determine files to be migrated from a first storage region to a second storage region is reduced. A file service system coupled to the storage system for providing a first storage region and a second storage region stores identifiers of files that have been accessed by a client, in accessed file identifier information and determines the files to be migrated from the first storage region to the second storage region based on metadata of the files stored in the first storage region and the accessed file identifier information.

Abstract: In order to provide HSM that can effectively use the storage capacity of an upper Tier in an HSM system, a lower Tier of the HSM system detects a group of files having the same data content from a plurality of files stored in the lower Tier, and keeps at least one of the real data of the group of files having the same data content while deleting the rest of the data. The upper Tier receives the process result from the lower Tier. Then, in response to a read request from the host computer that specifies a file included in the group of files and transferred to the upper Tier from the lower Tier, the upper Tier identifies the at least one of the data that is kept and corresponding to the specified file, and responds to the host computer.

Abstract: The system of the present invention curbs an unnecessary inter-tier file migration and provides an inter-tier file migration that conforms to the utilization state. The hierarchical storage management system respectively migrates a frequently accessed file to the upper Tier, and an infrequently accessed file to the lower Tier. This system carries out inter-tier file migration in conformance with the utilization state. This system provides functions for anchoring a Tier for storage for a specified file, and for not permitting an inter-tier file migration.

Abstract: In acquiring a snapshot, when data in a P-VOL is updated, it is determined whether the same data as target data to be stored in a certain second storage area specified by a certain second address of a D-VOL is already stored in a different second storage area specified by a different second address of the D-VOL, the target data being the differential data generated by the update. When the same data as the target data is stored, the target data is not newly stored in the D-VOL, and the different second address, specifying the different second storage area where the same data is stored, is registered in a snapshot management table (CoW table), in association with a certain first address specifying a certain first storage area where the data from which the target data has been generated is stored.

Abstract: A lower header 10 into which low temperature liquid is flowed and an upper header 16 are connected with each other via a plurality of outer heat exchange tubes 22. A plurality of inner heat exchange tube 24 are respectively provided in the corresponding outer heat exchange tubes 22 at a region of an inflow end portion of each outer heat exchange tube 22. An annular passage 23 is defined between an inside surface of each outer heat exchange tube 22 and an outside surface of each inner heat exchange tube 24 for flowing low temperature liquid. Each annular passage 23 is communicated with the lower header 10.

Abstract: A semiconductor rectifying diode includes a first semiconductor region of one conductivity type, a plurality of third semiconductor regions of the other conductivity type provided on one surface of said first semiconductor region to be spaced a distance W, and a main electrode provided on said one main surface to in ohmic contact with said first semiconductor region and in contact with said third semiconductor regions through the Schottky barrier. To reduce reverse leakage current a relation of 2wo<W.ltoreq.3D is satisfied, where D is the depth of said third semiconductor regions and wo is the width of a depletion layer spread to said first semiconductor region by a diffusion potential of the pn junction formed between said first semiconductor region and said third semiconductor region.

Abstract: A semiconductor rectifying diode includes a first semiconductor region of one conductivity type, a plurality of third semiconductor regions of the other conductivity type provided on one surface of said first semiconductor region to be spaced a distance W, and a main electrode provided on said one main surface in ohmic contact with said first semiconductor region and in contact with said third semiconductor regions through the Schottky barrier. To reduce reverse leakage current a relation of 2wo<W.ltoreq.3D is satisfied, where D is the depth of said third semiconductor regions and wo is the width of a depletion layer spread to said first semiconductor region by a diffusion potential of the pn junction formed between said first semiconductor region and said third semiconductor region.

Abstract: A non-destructive screening device for a glass diode includes a first circuit which determines a semiconductor element is acceptable when detecting a current oscillation caused by a micro plasma oscillation arising when the semiconductor current avalanche, and a second circuit which determines that the semiconductor element is unacceptable when detecting a void discharge due to a detrimental void, when a saw tooth signal pulse, which is to be built up to a level corresponding to the avalanche operation of the semiconductor and restricted to a current from a constant current source, is applied in a reverse direction to a circuit including the semiconductor element passivated with glass and a resistor connected in series thereto. According to the above discriminating operations, a material to be inspected may be screened in a non-destructive condition.