Hitachi, Ltd.

Japanese National Railways

Renesas Technology Corp.

Hitachi Electronics Engineering Co., Ltd.

Satoru Kishimoto

Yoji Sunada

Yoji Nakatani

Mitsunori Satomi

Fukuo Iwaya

Youji Nakatani

Makoto Ito

Morimasa Shirozume

Yasushi Shirota

Takahiko Mochinaga

Kunio Takeshita

Yoshiro Fukazawa

Yoshio Ando

The present invention provides a storage subsystem capable of realizing efficient data migration and high access performance. During migration of data between storage subsystems, data migration methods are selected between a 'PUSH' type and a 'PULL' type method based on a data migration policy set in advance to perform data migration processes. An access characteristics of a file and a folder storing the file are determined based on a file access frequency or a final access date and time information in a migration source storage subsystem, and the migration order of a file group determined to have a high possibility of being accessed during data migration is changed between the &#x201c;PUSH&#x201d; type and the &#x201c;PULL&#x201d; type.

Storage system, computer system and data migration method

In a first file storage apparatus, a first controller, which manages a first file system comprising a plurality of files, transfers a copy of the first file to a second file storage apparatus when managing the first file, manages the copy of the first file as a first replication file, configures the replication destination of the first replication file in the first file as a first pointer and, when processing a second file as a de-duplication target file, manages the first replication file as a copy of the first file and second file, configures a first pointer in the second file, and deletes the first data on condition that the storage destination of the first data which comprises the first file has been configured in the first file, or deletes the second data on condition that the storage destination of the second data which comprises the second file has been configured in the second file.

Storage system and file management method

An object of the present invention is to enable precise and easy adjustment of clock skew. A clock distribution circuit is designed and the placement and routing of the entire chip including the clock distribution circuit follows. Then the clock skew value is calculated and whether the calculated clock skew exceeds a target value is checked. When the clock skew exceeds the target value, the outputs of some driver elements are disconnected or connected to adjust the clock skew. The steps disconnecting or connecting the outputs of the drivers are repeated until the clock skew becomes equal to or smaller than the target value.

Placement and routing method for optimizing clock skew in clock distribution circuit

For optically measuring rail displacement, a light projector with a slit plate, a reflection mirror for light projection, a reflection mirror for light reception and a light receptor with a slit plate are installed at specified distances from one another on the underside of the body of a track inspection car on both sides in the longitudinal direction thereof. The light projector, the reflection mirror for light projection, the reflection mirror for light reception and the light receptor are arranged so that the light emitted from the light source in the light projector passes through the slit and, being reflected by the reflection mirror for light projection, is converged onto a measuring axis connecting the points as to which measurement is being made on the opposed rails which constitute the track at at least one of the rails to form a bright spot or band of light. The light receptor receives only the light from the rails at said measuring axis via the reflection mirror for light reception and then the slit in said receptor. In the light receptor a deviation of the reference measuring points indicated by movement of the bright spot or band during the running of the track inspection car along the track is detected; and by comparing the deviation with the position of said reference measuring points when the rails are in the correct position, the rail displacement can be measured.

Method and apparatus for optical method of measuring rail displacement

A track displacement detecting and measuring system in which track displacement data are obtained as usual for a unit chord length of the track according to the conventional three-point measuring method by sensors mounted on three predetermined parts of a track inspection car, and such measured data are processed by an arithmetic or processing device of relatively simple structure to detect the amount of track displacement occurring over a track distance which is two or four times the unit chord length. In the system, an improved gyro device free from the adverse effect of rolling of the car is employed so as to permit precise detection of vertical track displacement irrespective of the track distance. The system includes reflecting members of stainless steel disposed at a predetermined angle with respect to the track, a laser pulse projector, a reflected pulse receiver and a signal processing circuit so that errors of distance marks used for the recording of measured data can be corrected stably and with high precision.

Track displacement detecting and measuring system

Growing community of inventors

Tokyo, Japan

Satoru Kishimoto