Abstract: A magnetic recording and reproducing apparatus according to the invention involves unloading a magnetic tape after the tape is positioned to one of its unloading regions which is located approximately in the middle of a lengthwise tape area where user data have been recorded. Such unloading regions are located at predetermined intervals along the magnetic tape. Through designation of an operation mode, the apparatus of the invention also permits selecting one of two unloading regions to which the magnetic tape is positioned before being unloaded. One of the two regions is located approximately in the middle of the user data-packed tape area, the other region designated by a host device. This manner of unloading allows the inventive apparatus to access desired locations on the magnetic tape at a significantly higher speed than conventional devices.

Abstract: A magnetic recording and reproducing apparatus according to the invention involves unloading a magnetic tape after the tape is positioned to one of its unloading regions which is located approximately in the middle of a lengthwise tape area where user data have been recorded. Such unloading regions are located at predetermined intervals along the magnetic tape. Through designation of an operation mode, the apparatus of the invention also permits selecting one of two unloading regions to which the magnetic tape is positioned before being unloaded. One of the two regions is located approximately in the middle of the user data-packed tape area, the other region designated by a host device. This manner of unloading allows the inventive apparatus to access desired locations on the magnetic tape at a significantly higher speed than conventional devices.

Abstract: In a data recording apparatus and its method, data is compressed in units of a stated data block, it is detected in units of the data block whether or not data extension has occurred in consequence of the compression processing. Then, the compressed data is recorded on a recording medium in the case where the data extension has not detected, and on the other hand, in the case where the data extension has detected, the original data is recorded on a recording medium with respect to a stated number of data blocks subsequent to the data block in which the data extension has occurred. Thereby, a data recording apparatus and its method can be realized with a simple construction, which can record non-compressed original data on the recording medium with respect to a string of data in which the data extension is apt to occur, and thus can alleviate bad influence of data extension which occur in consequence of the compression processing.

Abstract: A circuit board unit that has a number of data processing blocks and a programmable logic array that controls the operation of the processing blocks to perform respective processing operations includes an external self-diagnosis program storage device connected through an interface unit to the programmable logic array, so that when the program storage device is connected a self-diagnosis program is fed to the programmable logic array that then causes the processing blocks to perform a self-diagnosis operation.

Abstract: A recording/reproducing apparatus by which recording data can be retransferred and a bit error rate can be greatly improved by a simple arrangement. Recording data REC is transferred as well as stored in a record buffer 30 in which the recording data REC of the number of blocks corresponding to a simultaneous reproducing time is sequentially stored and when the recording data REC is retransferred, the recording data REC stored in the record buffer 30 is read and retransferred. Further, during reproduction, reproducing data PB is sequentially reproduced through the record buffer 30 however, when a retransfer which occurred during recording is detected in the reproducing data PB, the reproducing data is reproduced without passing through the record buffer 30.

Abstract: A servo system for a motor having a rotor that includes a phase detector circuit for detecting a rotational phase of the rotor and for defining a plurality of angular positions of the rotor, each angle between adjacent angular positions being of the same size, a rotating device for rotating the rotor at a predetermined constant rotational speed, a speed detector circuit for detecting a rotational speed of the rotor at each of the angular positions, an error detector circuit for detecting errors of the speed detector circuit at each of the angular positions when the rotor is rotated at the predetermined constant rotational speed, a memory for storing the detection errors at each of the angular positions, and a servo control circuit for controlling a rotational speed and/or phase of the rotor in accordance with the rotational speed detected by the speed detector circuit and the detection errors read from the memory.