Abstract: Embodiments of the present invention help to suppress adverse effects on the host computer operation caused by saving a segment table. According to one embodiment, a hard disk drive (HDD) creates a segment table to associate addresses of user data in a flash memory with LBAs in a magnetic disk. The HDD updates the segment table in a DRAM and saves it to the flash memory at a specific timing. The HDD creates a journal indicating an update of the segment table and saves it to the flash memory. The segment table and the journal in the flash memory enable the latest segment table to be restored. If the HDD receives a predetermined command from a host computer, it saves the segment table in the DRAM into the flash memory.

Abstract: A disc storage apparatus includes at least one disc having at least one recording surface, at least one head associated with the at least one recording surface for recording data on the at least one recording surface, a decoder circuit which receives coded data from the at least one head, decodes the coded data to parallel data, and outputs the parallel data, and a disc control unit which receives the parallel data from the decoder circuit and outputs the parallel data outside the disc storage apparatus. The apparatus may further include a host interface control unit coupled to a host computer and the disc control unit, wherein the disc control unit outputs the parallel data to the host computer via the host interface control unit, and a buffer memory which stores the parallel data to be outputted to the host computer.

Abstract: The actual data recording area on a recording medium is expanded by reducing a gap area between blocks of data for compensating for a delay time of data conversion while recording and reproducing data in a data recording and reproducing device. Based on a servo sector signal, a data sector generator circuit generates a write data sector signal indicating a timing of data recording in a data recording area, and outputs the write data sector signal to a delay circuit and a selector having two input ports and one output port. The delay circuit generates a read data sector signal by delaying the write data sector signal by a certain period, and outputs the read data sector signal to the selector. The selector outputs the write data sector signal when a write mode signal is active, and outputs the read data sector signal when the write mode signal is inactive.

Abstract: A magnetic disk recording and reproducing apparatus comprising a unit for inserting an error correcting code related to control information into said control information on data; a recording control unit for recording in a plurality of sectors formed by dividing the recording area of a magnetic disk, each sector having an ID area for recording said control information and a data area, provided adjacent to and behind said ID area, for recording said data; and a error correcting unit for correcting said control information of said ID area by said error correcting code before data is read from said data area corresponding to said ID area or data is recorded in said data area corresponding to said ID area.

Abstract: A magnetic disc apparatus is a parallel recording type magnetic storage apparatus employing a dedicated servo system, wherein one of a plurality of data recording surfaces is used as a servo surface, the remaining even surfaces are used as ordinary recording surfaces, and the remaining one recording surface is used as a data recording surface which serves as a spare track or a spare sector when a defective track or a defective sector occurs. Since a microprocessor recognizes a defective track or a defective sector before writing data, if a defective track or a defective sector is produced, a normal track or sector is coupled with a spare track or a spare sector when a defective track or a defective sector is produced, and thereafter data is written into the magnetic storage apparatus.

Abstract: A magnetic disk recording and reproducing apparatus comprising a unit for inserting an error correcting code related to control information into said control information on data; a recording control unit for recording in a plurality of sectors formed by dividing the recording area of a magnetic disk, each sector having an ID area for recording said control information and a data area, provided adjacent to and behind said ID area, for recording said data; and a error correcting unit for correcting said control information of said ID area by said error correcting code before data is read from said data area corresponding to said ID area or data is recorded in said data area corresponding to said ID area.

Abstract: A data processing method of recording data on a recording medium mounted on an information recording apparatus. The data processing method includes the steps of dividing, in a disk controller, parallel data constituted by p bits transferred from a high-rank device into data each having q bits, where p and q are numbers; transferring the data each having q bits from the disk controller to an encoder as parallel data constituted by q bits; encoding, in the encoder, the data each having q bits to generate recording signals corresponding to data to be recorded; and recording the recording signals on the recording medium, thereby recording the data to be recorded on the recording medium.

Abstract: A disk type recording and reproducing apparatus includes a disk type recording medium having a plurality of tracks and having stored on each of the plurality of tracks a position signal indicating positions on the tracks; a drive section for rotating the disk type recording medium; a dual head separately incorporating a reading head for reading from the disk type recording medium and a writing head for writing into the disk type recording medium; a head drive section for moving the dual head; means for controlling the head drive section by a controlled variable in compliance with a position signal read from the disk type recording medium using an object track and the reading head; and memory means for storing quantity information used to correct the controlled variable of the means for controlling the head drive section.

Abstract: A magnetic disk drive has magnetic disks having tracks and a number of sectors forming each track. The tracks have an ID few track format and the drive is divided into a plurality of notches. The drive also includes a memory and a defect sector list, sector replacement list, defect track list and replacement track list, each of which is stored in the memory. Defective sectors and tracks in each notch are slipped during formatting, and further defective sectors and tracks detected subsequent to the formatting are skipped. Spare sectors in the notch are provided in a spare region to accommodate the slipped and skipped sectors and tracks, respectively. The defective sector list is supervised as a two stage table to reduce the required memory size for maintaining the list and to decrease the time required for searching the list.

Abstract: A disc storage apparatus includes at least one disc having at least one recording surface, a disc control unit for receiving a first number of write data, and outputting, through a plurality of lines, a second number of write data selected from the first number of write data, where the first number of write data and the second number of write data are each at least two write data, an encoder circuit coupled to the disc control unit through the plurality of lines for receiving the second number of write data from the disc control unit through the plurality of lines, encoding the second number of write data in parallel to produce coded data, and outputting the coded data for recording on the at least one recording surface, and a microprocessor for designating the second number of write data to be selected from the first number of write data, outputted by the disc control unit through the plurality of lines, and received by the encoder circuit from the disc control unit through the plurality of lines.

Abstract: A disk type recording and reproducing apparatus includes a disk type recording medium, and a dual head including a reading head and a writing head. A center of the core of the reading head is shifted in the radial direction of the disk type recording medium relative to a center of the core of the writing head. The disk type recording medium has a plurality of recording tracks each having a plurality of sectors. Each of the sectors has an ID division provided ahead of a data division disposed in the circumferential direction of the disk type recording medium. The ID division has recorded therein identification information identifying the sector. A center line of the ID division is shifted in the radial direction of the disk type recording medium relative to a center line of the data division by a distance equal to a distance by which the center of the core of the reading head is shifted in the radial direction of the disk type recording medium relative to the center of the core of the writing head.

Abstract: A rotary storage device includes a plurality of disk units, an upper-level interface circuit, a cache controller, a cache memory, and a control processor. In each disk unit, the storage area of each disk is subdivided into an ordinary user data area and a secondary cache data storage area including a group of consecutive cylinders. Data overflowed from the cache memory is sequentially written in the secondary cache data storage area so as to be later transferred therefrom to areas of the user data area according to addresses inherent thereto when traffic of upper-level input/output processing is relatively low. In the case of when data is sought to be accessed in the cache memory during a data read operation, access operations are performed first to the secondary cache data storage area and then to the user data area.

Abstract: A disc storage apparatus includes a disc having at least one recording surface, a head associated with the recording surface for recording data on the recording surface during a data write operation, and for reproducing data from the recording surface during a data read operation, a disc control unit for receiving data and outputting parallel data during the data write operation, and for receiving parallel data and outputting data during the data read operation, and an encoder/decoder circuit for receiving the parallel data from the disc control unit and outputting data to the head to be recorded on the recording surface during the data write operation, and for receiving from the head data reproduced from the recording surface and outputting parallel data to the disc control unit during the data read operation.

Abstract: A magnetic disk recording and reproducing apparatus including a unit for inserting an error correcting code relating to control information in the control information, the control information relating to data, a recording control unit for recording the control information and the data in a recording area of a magnetic disk, the recording area having a plurality of sectors, each of the sectors having an ID area for recording the control information and a data area for recording the data, the data area corresponding to the ID area and being provided adjacent to and behind the ID area in the same sector as the ID area, and an error correcting unit for correcting errors in the control information in the ID area using the error correcting code before the data in the data area corresponding to the ID area and provided in the same sector as the ID area is read or recorded.

Abstract: A cache control method and a rotary storage device are capable at a low cost, of improving the hit rate and minimizing the processing time in the event of a miss hit. The rotary storage devices includes a plurality of disk units, an upper-level interface circuit, a cache controller, a cache memory, and a control processor. In each disk unit, the storage area of each disk is subdivided into an ordinary user data area and a secondary cache data storage area including a group of consecutive cylinders. Data which has overflowed from the cache memory is sequentially written in the secondary cache data storage area so as to be later transferred therefrom to areas of the user data area according to addresses inherent thereto when traffic of upper-level input/output processing is relatively low. In the case of a miss hit of the cache memory during a data read operation, access operations are performed first to the secondary cache data storage area and then to the user data area.

Abstract: A data transfer control apparatus for communicating data between a host device and an input/output device through a main buffer memory for temporarily holding the data, wherein a sub-buffer memory is disposed at least either between the main buffer memory and the host device or between the main buffer memory and the input/output device for temporarily storing the data, the amount of data stored in the sub-buffer memory is detected, access requests to the main buffer memory on the side of the host device or the input/output device are outputted in accordance with the detected data amount, and one of the access requests to the main buffer memory is selected in accordance with the priority order to access the main buffer memory on the basis of the selected access request.

Abstract: The present invention relates to a magnetic disk control apparatus capable of utilizing a data region of a track. The data read/write controlling apparatus according to the present invention comprises a unit for serially reading a signal series constructed of a servo signal and data which has been recorded on a recording track; a unit for generating a first read/ write control signal in response to the servo signal of the read signal series; a unit for generating a second read/write control signal between the generation of the servo signal and a generation of a servo signal subsequent to the first-mentioned signal; a unit for writing given data into the data region of the recording track in response to the generation of the read/write control signal; and a unit for externally outputting data read out just after the read/write control signal is generated.

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.

Abstract: This invention relates to a biologically active substance which is a glycoprotein having a molecular weight of 3,000 to 5,000 and has activity to inhibit toxoplasma multiplication in homologous cells and heterologous cells.This invention also relates to a process for preparing the substance, immunoactive compositions containing the substance and use of the substance as a drug.

Abstract: This invention relates to a biologically active substance which is a glycoprotein having a molecular weight of 3,000 to 5,000 and has activity to inhibit toxoplasma multiplication in homologous cells and heterologous cells.This invention also relates to a process for preparing the substance, immunoactive compositions containing the substance and use of the substance as a drug.