Abstract: A helical type tape recording and reproducing system records blocks of user data-of predetermined size by reformatting the user data blocks into physical blocks that are recorded on tape. The system format includes helical tracks in which user data blocks are recorded and longitudinal tracks for storing address information relating to the physical layout of the tape and to the content of the recording in the helical area. The system includes a partition access bookkeeping feature that stores information relating to locations at which searching or recording has been performed during a current load of a tape in the system, which is useful in accomplishing efficient searching for user data recorded on the tape. The present invention is directed to system search capabilities, including longitudinal searching along the tape and searching in the helical recording area of the tape.

Abstract: A helical tape recording and reproducing system which has longitudinal physical address track for recording physical address data relating to the physical layout of the tape and a logical address track that contains data relating to the content of the recorded helical tracks. Each address track has recorded segments with each of said segments containing data corresponding to a particular pair of helical tracks recorded in said helical recording area. Each segment has a multiple bit front field of a first predetermined timing synchronization bit pattern, a first predefined synchronizing word, a multiple bit segment information field of data, a second predefined synchronizing word and a multiple bit rear field of a second predetermined timing synchronization bit pattern.

Abstract: A recording and reproducing system records blocks of user data of predetermined size by reformatting the user data blocks into physical blocks that are recorded on tape. Each physical block is recorded as a double frame on a set of successive helical tracks, preferably 32 tracks. The system has the capability of verifying whether a physical block has been accurately recorded, and if not, the system automatically rewrites the physical block downstream without stopping or repositioning the tape. If an accuracy verification confirmation does not occur until a next physical block is being recorded, the system demarks or invalidates that physical block being written, and rewrites both the failed physical block and that following physical block downstream of that physical block being written.

Abstract: A tape recording and reproducing system records blocks of user data of predetermined size by reformatting the user data blocks into physical blocks that are recorded on tape. Each physical block is recorded as a double frame on a set of successive helical tracks, preferably 32 tracks. The system has the capability of verifying whether a physical block has been accurately recorded, and if not, the system rewrites the physical block downstream without stopping or repositioning the tape. If an accuracy verification confirmation does not occur until a next physical block is being recorded, the system demarks or invalidates that physical block being written, and rewrites both the failed physical block and that following physical block downstream of that physical block being written.

Abstract: A phase detection control apparatus is disclosed for detecting any variable where the phase is discretely measured, as for example, in a motor having a tachometer of an optical type. The phase detection apparatus eliminates direction sensitivity and does not suffer from the misposition of any upper and lower limits. The apparatus achieves a phase lock without excessive overshoot and eliminates the possibility of reverse run away under any condition. Moreover, the circuitry is easily implemented with a relatively few number of circuit components and therefore accomplishes the desirable functional capabilities at relatively low cost.