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: 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: Disclosed is a method of access control for a disk drive whereby an access operation for, particularly, sequentially and alternately executing accesses is supported. A CPU of the present disk drive sequentially and alternately executes accesses to a plurality of data tracks on a disk in response to an access request generated from a host system. During the access operation, the CPU secures time for a look-ahead operation, the time corresponding to the difference between transfer rates. Thus, sequential and alternate access operation in which the number of seek operations can be reduced can be realized.

Abstract: Magnetic recording/reproducing apparatus in which partially-missed data has priority to be transferred to the host system as dummy data over optional data in order to minimize a frame skipping area caused by the dummy data, the dummy data which is used for executing data reproduction having sufficient continuity for a viewer.

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: Disclosed is a method of access control for a disk drive whereby an access operation for, particularly, sequentially and alternately executing accesses is supported. A CPU of the present disk drive sequentially and alternately executes accesses to a plurality of data tracks on a disk in response to an access request generated from a host system. During the access operation, the CPU secures time for a look-ahead operation, the time corresponding to the difference between transfer rates. Thus, sequential and alternate access operation in which the number of seek operations can be reduced can be realized.

Abstract: Magnetic recording/reproducing apparatus in which partially-missed data has priority to be transferred to the host system as dummy data over optional data in order to minimize a frame skipping area caused by the dummy data, the dummy data which is used for executing data reproduction having sufficient continuity for a viewer.

Abstract: A presentation supporting system is constructed to be space-saving and to allow compact packing under a non-service condition. In the presentation supporting system, the presentation conditions are adjusted adequately without much labor and time. The presentation supporting system of the invention has a table on which a subject matter is placed, a camera head unit for taking a visual image of the subject matter, a camera supporting base member projecting upright from a rear side of the table, and a folding camera supporting arm member to which the camera head unit is fixed. The folding camera supporting arm member is stretched upward under a service condition and is folded under a non-service condition. The presentation supporting system includes a control circuit having an EEPROM which stores settings of control buttons on a front operation panel and a control panel when a key set button is activated.

Abstract: Servo sector numbers for identifying servo areas are recorded at predetermined positions in the respective servo areas on a disk. A plurality of data sectors are arranged between the respective servo areas. When a data sector is to be accessed, a servo circuit extracts a corresponding servo sector number. A CPU generates a data sector pulse at a timing corresponding to the start position of the data sector on the basis of the extracted servo sector number. The start position of the data sector is accurately detected in accordance with this data sector pulse, thereby reliably performing data access.

Abstract: A presentation supporting system is constructed to be space-saving and to allow compact packing under a non-service condition. In the presentation supporting system, the presentation conditions are adjusted adequately without much labor and time. The presentation supporting system of the invention has a table on which a subject matter is placed, a camera head unit for taking a visual image of the subject matter, a camera supporting base member projecting upright from a rear side of the table, and a folding camera supporting arm member to which the camera head unit is fixed. The folding camera supporting arm member is stretched upward under a service condition and is folded under a non-service condition. The presentation supporting system includes a control circuit having an EEPROM which stores settings of control buttons on a front operation panel and a control panel when a key set button is activated.