Abstract: According to one embodiment, a disk comprises an area which comprises a plurality of data tracks and is partitioned into a first segment and a plurality of second segments. A controller detects that a segment to be refreshed next is one of the plurality of second segments. The controller saves data stored in the one of the plurality of second segments into the first segment when a segment to be refreshed next is the one of the plurality of second segments.

Abstract: According to one embodiment, a disk controller includes a receiver, a read-modify-write controller, and a wait controller. The receiver receives data in units of predetermined data length. The read-modify-write controller performs a read-modify-write operation when the receiver receives the data to write the data to a sector on a disk medium the rotation of which is controlled. The sector is longer than the predetermined data length. The wait controller delays the start of the read-modify-write operation by the read-modify-write controller for within the time which the disk medium takes to rotate once and which is substantially the same as the time required to control the read-modify-write operation.

Abstract: According to one embodiment, a disk has a set of tracks thereon. A controller performs refresh control for reading data by a head from a track on the disk to be refreshed and for writing the read data by the head to a spare track adjacent to the track from which the data has been read. The controller switches the track from which the data has been read to a new spare track after the writing.

Abstract: According to one embodiment, a disk comprises an area which comprises a plurality of data tracks and is partitioned into a first segment and a plurality of second segments. A controller detects that a segment to be refreshed next is one of the plurality of second segments. The controller saves data stored in the one of the plurality of second segments into the first segment when a segment to be refreshed next is the one of the plurality of second segments.

Abstract: According to one embodiment, the controller controls a data refresh operation. The data refresh operation comprises a refresh-data read operation of reading L blocks of data by a head from a track to be refreshed on a disk, a data backup-write operation of writing the read data by the head to a backup-track on the disk, and a refresh-write operation of writing the read data by the head to the track to be refreshed after the backup-write operation. The controller sets the number L of blocks to a value that satisfies conditions for completing the backup-write operation and the refresh-write operation within a time corresponding to N revolutions of the disk from completion of the refresh-data read operation.

Abstract: According to one embodiment, a hard disc apparatus comprises a disc, wherein areas between neighboring servo areas are allocated to data areas including data sectors, a head module, and a storage module configured to store head alignment data, wherein the head alignment data are defined for the data areas, and includes information indicating an interval from the servo area to a first data sector, information indicating a data area in one track, a first data sector which is a start sector of the track, and information indicating the presence/absence of a defective sector including a primary defect, and the start sector of a track including the defective sector is a data sector next to the defective sector.

Abstract: According to one embodiment, a disk controller includes a receiver, a read-modify-write controller, and a wait controller. The receiver receives data in units of predetermined data length. The read-modify-write controller performs a read-modify-write operation when the receiver receives the data to write the data to a sector on a disk medium the rotation of which is controlled. The sector is longer than the predetermined data length. The wait controller delays the start of the read-modify-write operation by the read-modify-write controller for within the time which the disk medium takes to rotate once and which is substantially the same as the time required to control the read-modify-write operation.

Abstract: According to one embodiment, the controller controls a data refresh operation. The data refresh operation comprises a refresh-data read operation of reading L blocks of data by a head from a track to be refreshed on a disk, a data backup-write operation of writing the read data by the head to a backup-track on the disk, and a refresh-write operation of writing the read data by the head to the track to be refreshed after the backup-write operation. The controller sets the number L of blocks to a value that satisfies conditions for completing the backup-write operation and the refresh-write operation within a time corresponding to N revolutions of the disk from completion of the refresh-data read operation.

Abstract: According to one embodiment, a disk has a set of tracks thereon. A controller performs refresh control for reading data by a head from a track on the disk to be refreshed and for writing the read data by the head to a spare track adjacent to the track from which the data has been read. The controller switches the track from which the data has been read to a new spare track after the writing.

Abstract: According to one embodiment, a hard disc apparatus comprises a disc, wherein areas between neighboring servo areas are allocated to data areas including data sectors, a head module, and a storage module configured to store head alignment data, wherein the head alignment data are defined for the data areas, and includes information indicating an interval from the servo area to a first data sector, information indicating a data area in one track, a first data sector which is a start sector of the track, and information indicating the presence/absence of a defective sector including a primary defect, and the start sector of a track including the defective sector is a data sector next to the defective sector.

Abstract: A CPU determines whether or not the disk access range designated by a read/write command from a host contains a defective sector. If the disk access range contains a defective sector, the CPU suspends disk access when a head has reached the defective sector. In this state, the CPU activates a buffer access circuit. The buffer access circuit copies data between an area of an alternate sector buffer and data buffer. The area of the alternate sector buffer stores data corresponding to the data written in the alternate sector allocated to the defective sector reached by the head.

Abstract: In a disk storage apparatus which can concurrently process a plurality of data streams specified by a host, it is determined whether an error has occurred in a write operation specified by a write command being executed. If it is determined that an error has occurred, the write command is retried regardless of whether or not the time spent performing the write operation until the present time is within a time limit specified by the write command.

Abstract: A CPU determines whether or not the disk access range designated by a read/write command from a host contains a defective sector. If the disk access range contains a defective sector, the CPU suspends disk access when a head has reached the defective sector. In this state, the CPU activates a buffer access circuit. The buffer access circuit copies data between an area of an alternate sector buffer and data buffer. The area of the alternate sector buffer stores data corresponding to the data written in the alternate sector allocated to the defective sector reached by the head.

Abstract: A disk control apparatus according to the present invention comprising a disk controller for controlling a circuit which controls read operation for reading data from a disk and a CPU for controlling the circuit and the disk controller. The disk controller comprises a buffer memory for storing data being for transferred between a host and the disk controller and a notification section for notifying the CPU that a first state in which an all buffer region of the buffer memory is stored with data to be transferred to the host transits to a second state in which a predetermined space occurs in the buffer region of the buffer memory as a result of transferring data to the host. The CPU comprises a main control section for stopping power supply to the circuit during the first state and for supplying power to the circuit in response to a notification from the notification section.

Abstract: A disk controller (HDC) reads requested data from a disk in accordance with a read command from a host system, and stores the data in a buffer memory. The HDC reads successive data, together with the requested data, and stores the data in the buffer memory. When a repeat access request is issued from the host system, the HDC temporarily stops disk access which has been continued. A CPU determines the amount of data stored in the buffer memory by disk access on the basis of a limit value set in a limit register. The HDC reads requested data corresponding to the repeat access request from the buffer memory and transfers the data to the host system.

Abstract: A resin compound for a molding die, a molding die made of the resin compound, and a molding method using the molding die are disclosed. The resin compound includes thermoplastic resin, inorganic fiber reinforcing material and inorganic particle filler, has a flexural strength of 1000 kgf/cm.sub.2 or more and a modulus of elasticity in bending of 70000 kgf/cm.sup.2 or more, and allows machining. A deflection temperature under flexural load of the compound may be 180.degree. C. or more. From this compound, it is possible to provide a core, a cavity block or the like of molding dies which can be accurately finished by machining finishing with a low cost and within a short term, have durability and allows recycling. The molding dies can be applied to various molding methods, and provide accurate molded products with a low cost.

Abstract: In this invention, there is provided a magnetic disk apparatus and a command processing method of the magnetic disk apparatus in which the cache function can be effectively performed even in a case where read commands and write commands are alternately issued and the read or write command can be executed at high speed. An HDC includes a read address holding register in which an access starting address is set when a read command is issued from a host system and which holds an access address associated with the read command and a write address holding register in which an access starting address is set when a write command is issued from the host system and which holds an access address associated with the write command.

Abstract: When a write command is issued by a host computer data promptly transferred in response to the write command is stored in a write area of the data buffer. Thereafter, the start address of a read/write area is changed into the start address of the write area, data transferred from the host computer is stored in the data buffer to be sequential to the data stored in the write area. Thereafter, processing of sequentially the data stored in the read/write area in a magnetic disk is performed. When a read command is issued, the write area is set not to overlap the read/write area.

Abstract: A buffer memory is prepared to temporarily store data sequentially read out from consecutive storage positions of a magnetic disk. When a read request is received from a host system, and an HDC reads out the requested data from the magnetic disk, the readout data is written in a buffer area in the buffer memory, which is assigned by a CPU and designated by a buffer management data portion, from the start position to the end position of the area. If the requested data exceeds the capacity of this area, the start address returns to a position indicated by a new start buffer address set in the buffer management data portion which is set by the CPU, e.g., a middle point in the buffer area, and the succeeding readout data is stored in the buffer area from the middle point to the end position. The requested data stored in the buffer memory is sequentially transferred to the host system.

Abstract: A method of separating a transfer sheet from an image bearing member electrostatically adhered thereto for an electrostatic recording system of transfer type, in which a toner image is formed on the image bearing member and then electrostatically transferred to the transfer sheet placed in contact with the member. The image bearing member is bent together with the transfer sheet at the position subsequent to the image transfer position, whereby the transfer sheet is separated from the surface of the member due to toughness of the sheet.