Abstract: For a computer system having a central processing unit, an external storage unit which records data in a count-key-data (CKD) format, and a storage control unit with a cache memory for controlling data transfer between the external storage unit and the central processing unit, a computer system and data search method is provided which can prevent the performance of the central processing unit from being lowered and can eliminate signal transfer between the central processing unit and storage control unit during most of a data search operation period, by disconnecting the storage control unit from the central processing unit. During the data search operation, upon reception of a search command for the first record, a quasi completion report is issued to disconnect the storage control unit from the central processing unit. The storage control unit executes the search operation by using data loaded in the cache memory of the storage control unit. After data is searched, a search completion report is issued.

Abstract: A data transfer control system in a data transfer apparatus including a plurality of data processing units having different data transfer speeds and a temporary holding circuit provided between the data processing units for temporarily holding data transferred between the data processing units. The data transfer apparatus sends a transfer request for data corresponding to a data storage capacity of the temporary holding circuit of the data transfer apparatus to the data processing unit on the side of sending data and sends a transfer request for data corresponding to the data storage capacity of the temporary holding circuit after an elapse of a delivering time of data to an information processing unit on the data transferred side of the temporary holding circuit from the time the data transfer request is sent until the requested data from the data processing unit on the data sending side reaches the temporary holding circuit of the data transfer apparatus.

Abstract: A bias magnet unit has a permanent magnet that applies a bias magnetic field to an optical spot on a magneto-optical disk. A driving coil rotates the magnet in order to change a polarity of the bias magnetic field. A sensor detects the intensity and polarity of the bias magnetic field to confirm the rotational position of the magnet after it has been rotated. A linkage structure that is connected between a magnet holder of the magnet unit and the housing has arms that drive the magnet unit between two positions, one in which the magneto-optical disk cartridge can be inserted into the device and another in which the disk is loaded onto the spindle motor for recording/playback. Overall, the components of the device cooperate structurally to provide a relatively thin device structure having low power consumption.

Abstract: A personal information display system is provided with a portable information display device for reading information to be used from a storage medium, a communication network for transmission of information, input/output apparatus for input/output of information, an input/output control apparatus connected between the communication network and the input/output apparatus, an information control apparatus having a hierarchical memory connected to the communication network, and an information output apparatus connected to the information control apparatus to transfer information to the storage medium of the portable information display device.

Abstract: A method of accessing a multifile storage medium and a library system. The library system includes recording/reproducing apparatuses for performing a recording/reproducing operation on the multifile storage medium, a plurality of recording/reproduction control units for controlling transaction of information with a host, a plurality of buffers provided between the recording/reproduction control units and the recording/reproducing apparatuses, a library control unit for controlling the whole library system, a directory for recording correspondence between the individual multifile recording media and a plurality of files stored therein, a shelf for housing the multifile storage media and handling devices. The plural buffers can be accessed independently of one another. Plural files are transferred between the buffers and the storage medium on a file-by-file basis. The access requests to the files are disposed of within the buffer.

Abstract: Increased memory capacity for a magnetic disk device is realized without degrading information error rate, by making the number of sectors at a given circumference of the disk variable in accordance with a radial direction of a disk. The number of sectors is made variable by deciding a predetermined information error rate from a ratio of reproduced signal output to noises of head, disk and amplifier at a maximum recording and reproducing frequency at a certain radial position along a disk.

Abstract: A data transfer control system in a data transfer apparatus including a plurality of data processing units having different data transfer speeds and a temporary holding circuit provided between the data processing units for temporarily holding data transferred between the data processing units. The data transfer apparatus sends a transfer request for data corresponding to a data storage capacity of the temporary holding circuit of the data transfer apparatus to the data processing unit on the side of sending data and sends a transfer request for data corresponding to the data storage capacity of the temporary holding circuit after an elapse of a delivering time of data to an information processing unit on the data transferred side of the temporary holding circuit from the time of the data transfer request is sent until the requested data from the data processing unit on the data sending side reaches the temporary holding circuit of the data transfer apparatus.

Abstract: A disk array system having a plurality of disk units includes an upper-level data transfer controller for controlling transfer of data to and from an upper-level apparatus, a data buffer for temporarily storing therein data from the upper-level apparatus, a drive data transfer controller for controlling the data transfer between the buffer and the units, and a main microprocessor for controlling the the transfer controllers. When transferring data, the microprocessor indicates an address to be used in the buffer and a distribution mode of data to the data transfer controllers so that the data transfer is conducted thereafter without intervention of the microprocessor. During the transfer, the microprocessor can generate information for a subsequent data transfer to indicate the information to the transfer controllers. After a data transfer is terminated, the pertinent transfer controller can immediately execute the next data transfer, which increases the utilization efficiency of the data bus.

Abstract: Increased memory capacity for a magnetic disk device is realized without degrading information error rate, by making the number of sectors at a given circumference of the disk variable in accordance with a radial direction of a disk. The number of sectors is made variable by deciding a predetermined information error rate from a ratio of reproduced signal output to noises of head, disk and amplifier at a maximum recording and reproducing frequency at a certain radial position along a disk.

Abstract: In a system equipped with a plurality of magnetic disk devices, one magnetic disk device is used as a device (master unit) for generating reference signals for rotating other plurality of devices in synchronism. Other one or more magnetic disk devices (slave units) are rotated in synchronism following the reference signals generated from the master unit. In order to maintain the synchronism of revolution between the master unit and the slave units, the conditions of revolution of the two spindle motors are compared to maintain the synchronism of revolution. Index pulses recorded on the magentic disks of the master unit and the slave units are used as reference signals for maintaining synchronism of revolutions. Index pulses from the master unit and the slave units are compared to find a phase difference signal and a period difference signal, and the rotational speed of the slave units is compensated by using these two signals.

Abstract: Every other input pulse is extracted from an input signal containing alternate phase-advanced and phase-delayed pulses read out of a magnetic disk unit, a magnetic tape unit or the like. Output pulses in synchronism with the pulses thus extracted are produced. This extraction may be effected only during a predetermined length of time after staring application of the input pulses at the time of pull-in of a phase sync circuit. Whether phase synchronization is to be effected in accordance with advanced-phase or delayed-phase input pulses is determined from time to time as required.

Abstract: A fast calculation circuit for a cyclic redundancy check code of compressed data having a compressed area and an uncompressed area, the compressed area containing at least a data byte representative of the content of consecutive same data bytes and a data byte representative of the number of consecutive same data bytes.

Abstract: A wire with a coated layer for bonding to a joint body by ultrasonic vibration, the coated layer of said wire comprising urethane resin having formulated therein a brominated epoxy resin.

Abstract: A method of data compression for recording data on a recording medium such as a magentic tape, a method of data restoration for data which has been compressed for recording, and an apparatus of data compression and restoration prescribe the data to be compressed based on type or value and encode the compression object data, thereby reducing the number of bits necessary to indicate the compression object data. Compression is implemented only for consecutive data fewer in number of repeating consecutive bytes than a certain number, thereby reducing the number of bits necessary to indicate the number of bytes of the consecutive data. A compression mark indicative of compression is appended to the compressed data, consisting of data made by encoding the compression object consecutive data and data indicating the number of bytes of the data, either at the front or rear of the compressed data, whereby an input data string can be compressed drastically and compressed data, even including errors, can be restored.

Abstract: In a magnetic disk unit for recording/reproducing data onto/from a disc by means of a magnetic head on the basis of a seek command and a recording/reproducing command received from a host processor, the execution of the data reproducing command for the disk is started upon detection of a state that the magnetic head has sought on a desired track to an extent that the centering state is still unstable but the data can be reproduced, and the execution of the data recording command is started upon detection of a condition that the magnetic head has reached the stable centering state on the desired track after the detection of the reproducible state.