Hitachi, Ltd.

Nippon Telegraph and Telephone Public Corporation

Kogyo Gijutsuin

Hitachi Vlsi Engineering Corp.

Nobuo Saito

Shigeru Yoshizawa

Atsushi Asano

Takashi Toyooka

Hirokazu Aoki

Minoru Hiroshima

Koichi Mayama

Yutaka Sugita

Takashi Kikuchi

Mamoru Sugie

Yuzo Kita

Hiroshi Fukuta

Shinsaku Chiba

Noboru Yamaguchi

Minoru Saitoh

Hirofumi Ohta

Hiroshi Suehiro

Yuji Arai

Nakahiko Yamaguchi

Keisuke Mise

Oichi Atoda

Itsuo Mikami

Gen-ichi Kamoshita

A data storage device for storing data strings each including units of data has a plurality of memory sections each for storing therein a table, a plurality of processor elements one provided for each of the tables and a controlling unit having an internal memory in which data strings are stored. The table contains a plurality of records each including a unit of data, a first index data representative of the number of units of data of a data string which the unit of data constitutes and a second index data unique to each individual data string. The processor elements access in parallel their associated tables under control of the control unit for data storage and data retrieval. The first and index data are generated by the controller for the purpose of data storage. For retrieval of data strings: a key data string is divided into units of data; retrieval keys are produced each from a combination of one of the divided units of data and a third index data representing the number of units of data of the key data string; second index data are retrieved in parallel in the tables of the data storage device with the retrieval keys so that a single second index data common to all of the retrieved second index data is found among them; and a data string corresponding to the found common second index data is outputted from the internal memory of the storage device.

Data string storage device and method of storing and retrieving data

In a memory device which has a plurality of recirculating type storage loops and in which information of the same addresses of the respective storage loops can be read and written in parallel, a memory device wherein information representing whether or not the corresponding storage loop is a bad or defective loop is written in a specified address of each of the storage loops.

Memory device with circulating storage loops

The present invention provides an improved method and apparatus for driving a magnetic bubble device, in which a d-c voltage supply and drive coils are connected to a bridge circuit consisting of four bi-directional switches, and alternating currents with steps (such as currents consisting of triangular waves or trapezoidal waves) are produced in the drive coils by suitably controlling the turn on or off of the bi-directional switches. As a result, the d-c level in the alternating current is not shifted by the variation in width of pulses which control the opening and closing of the bi-directional switches, and the magnetic bubble device is provided with a greatly improved operation margin.

Drive circuit for magnetic bubble device

In a shift register type memory device wherein a plurality of chips are connected to a single sense amplifier and wherein data to be stored is cyclically written into the chips, then when a predetermined loop within a chip for stored designated data is defective, the data is not stored in a loop within the chip adjacent to the defective loop, but is stored in a loop to be subsequently read out in a chip to be read out subsequently to the chip having the defective loop.

Shift register type memory device consisting of a plurality of memory

A third conductor is added to a pair of first and second parallel conductors transmitting signals, a part of which conductors are located in an alternating magnetic field. The three conductors are so arranged that the first and third conductors are symmetrical with respect to the center line of the second conductor, and the first and third conductors are interconnected at both extremities thereof.

Circuit arrangement for suppressing magnetic induction noise due to an

A field access magnetic bubble memory device including a memory chip applied with an in-plane magnetic field at need is disclosed. At a transient stop operation of the device before its interrupted state, an in-plane field is removed after it has been held for a predetermined period following the cessation of rotation thereof. The in-plane field may be increased upon the cessation of rotation thereof. At a transient start operation of the device after the interrupted state, an in-plane field having no rotation and the same direction as at the transient stop operation is applied for a predetermined period before the initiation of rotation thereof. The applied in-plane field may be increased upon the initiation of rotation thereof.

Field access magnetic bubble memory device

A shift register type memory having major and minor loops, wherein the number of bits of the major loop is large enough to permit data of at least two blocks to simultaneously exist in the major loop when one block is constituted of data of bits the number of which is equal to the number of the minor loops, and wherein before a particular block having been transferred out from the minor loops to the major loop is again transferred in to the minor loops after travelling round the major loop, the next block is transferred out from the minor loops to the major loop.

Shift register type memory

A shift register type memory device according to this invention includes on the same chip as that of an information storing medium, a functional part which identifies defect loops and controls the writing and reading of information so as to exclude them. The functional part includes a defect loop address memory which stores locations of the defect loops in the binary expression, and a common detector which reads out information from the defect loop address memory and information from storage loops.

Fault tolerant shift register type memory device

A magnetic bubble information writing device in which a conductor loop is disposed on the magnetic bubble propagation circuit and in which magnetic bubbles are generated by sending pulse current through the conductor loop, the device having a means which after having sent the bubble generating pulse current through the conductor loop, sends pulse current for annihilating stray bubbles through the same, the stray bubble annihilating pulse current having a polarity opposite to that of the bubble generating pulse current.

Magnetic bubble information writing device

In a magnetic bubble module comprising magnetic bubble chips disposed on substrates and driving coils surrounding the magnetic bubble chips, at least one of the substrates extends from the inside to the outside of the coils and serves as a heat transfer plate. The heat transfer plate includes at least one metal foil having a thickness smaller than a skin depth of the metal.

Magnetic bubble module

A bubble domain driving apparatus is provided in which a large memory device with a storage capacity of 256 megabits, for example, is divided into 64 smaller memory elements, each thereof comprising one or plurality of thin magnetic film strips for bubble domain, and each of the 4-megabit smaller memory elements is provided with its own coils for applying in the plane thereof bubble domain driving rotating fields with the coils adapted to be selectively energized.

Growing community of inventors

Mitaka, Japan

Nobuo Saito