Hitachi, Ltd.

Renesas Electronics Corporation

Shigeki Taira

Osamu Kawamae

Taku Hoshizawa

Harukazu Miyamoto

Yukari Katayama

Yasushi Nagai

Hiroshi Nakagoe

Takeshi Maeda

In the configuration performing a data processing by a hardware processing circuit (accelerator), to provide a technology capable of improving a poorness of processing efficiency by multiple accesses to the data, the following solving means are provided. A network data processing accelerator of the present network data processing apparatus comprises processing units corresponding to each processing of an encryption/decryption, a message authentication, and a checksum, and in the data processing including a combination of each processing, accesses for the same data of the memory and the like through a bus I/F unit and the like is collected together into one time, and a pipeline processing is performed using the least common multiple of the data processing unit of each processing.

Data processing apparatus

A digital data recording/reproducing method includes the steps of: interleaving data on a PI code for each PI code of a 208-row ECC block; and converting a short burst error into random errors by dispersing errors on the PI codes. Moreover, the digital data recording/reproducing method increases correction capability against several bytes to several tens bytes of errors generated at random without changing burst error correction length by performing this processing for respective PI codes by using interleave rules that are different as much as possible from one another.

Method of recording/reproducing digital data and apparatus for same

If a large minimum data unit for recorded data is used to record a small data amount of management information, the recording time is long, and furthermore when a WO (write once) is used as the recording medium, the number of recording operations is restricted. To solve the above problems, the present invention records data in a management area in units smaller than ordinary units for recorded data to suitably record information in a limited management area and thereby efficiently use the user data area. At that time, the present invention simplifies interleave processing usually applied to ordinary recorded data, and performs the simplified interleave processing on a data structure (for data of small size) of the present invention so as to ensure the signal processing compatibility between the ordinary data and data having the data structure according to the present invention.

Recording and reproducing data to/from a recording medium having a user data area and an information area for storing information about the recording medium

The DMA controller includes a peripheral device read unit to read states of peripheral devices, a state comparator, a transfer unit, a register, and a peripheral device write unit to write data in the peripheral devices according to the contents in the register when the DMA transfer is executed, an interrupt select unit selects one of plural interrupt signals to determine whether the peripheral device read unit, the state comparator and the transfer unit are at a timing to execute operations. Based on these operations the state comparator determines whether to start the DMA transfer, and the transfer unit executes data transfer between the peripheral devices.

DMA controller

A DMA controller achieving real-time control of a DMA transfer relating to periodically operated peripheral devices at a low cost and with low power consumption. A typical embodiment of the invention is a DMA controller having: a counter for counting time; a counter comparator comparing a value of the counter and a counter value indicating an expected time of a DMA transfer; a peripheral device read unit reading a register of the peripheral device to acquire a state of a peripheral device by; and a state comparator comparing a value of the register read by the peripheral device read unit and a start condition of the DMA transfer, in which, with being triggered by establishment of a comparison result by the counter comparator, in accordance with a specified order, a processing of updating the counter value indicating the expected time of a DMA transfer to a value indicating a next expected time, a read of the register of the peripheral device by the peripheral device read unit, a comparison by the state comparator, and a DMA transfer on the condition that the comparison result by the state comparator is established are executed.

If a large minimum data unit for recorded data is used to record a small data amount of management information, the recording time is long, and furthermore when a WO (write once) is used as the recording medium, the number of recording operations which can be performed is restricted. To solve the above problems, the present invention can record data in a management area in units smaller than ordinary units for recorded data to suitably record information in a limited management area and thereby efficiently use the user data area. At that time, the present invention simplifies interleave processing usually applied to ordinary recorded data, and performs the simplified interleave processing on a data structure (for data of small size) of the present invention so as to ensure the signal processing compatibility between the ordinary data and data having the data structure according to the present invention.

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Yokohama, Japan

Shigeki Taira