TH24338B - Datasets to save registers and synchronization of recording medium - Google Patents

Abstract

DC60 (28/06/43) System and method for accurately registering and synchronizing data sets on a recording medium containing a pre-recorded servo pattern. The recording medium relies on continuous movement for reading and/or writing data sets, interrupted by a stop at the end of the selected data set and a restart. During the continuous movement of the recording medium, a sensor coupled to the servo system reads a sequence of linear position register data, modulated to a pre-recorded servo pattern. An interlearner inserts the pre-recorded register data to provide a clean register message for the data set. When the recording medium tape drive is stopped, and the medium is retracted and the movement restarts, a recording message is read and inserted. The sensor reads and inserts the pre-recorded recording data again, and a comparison circuit compares the read and inserted recording messages with any pre-defined read and inserted recording messages and overlaps, and indicates the comparison pair. A data formatter coupled with a comparator circuit, in response to a pair indication, synchronizes the reading and/or writing of data sets on the recording medium. The system and method for accurately registering and synchronizing data sets on a recording medium that has a pre-recorded servo pattern. The recording medium relies on continuous movement for reading and/or writing data sets, which is interrupted by a stop at the end of the selected data set and a restart. During the continuous movement of the recording medium, a sensor coupled with a servo system reads a sequence of linear position register data, modulated to a pre-recorded servo pattern. An interlearner inserts pre-recorded register data to provide clean register information for the data set. When the recording medium tape drive is stopped and retracted, the medium and its movement restart, register information is read and inserted. The sensor reads and inserts the pre-recorded register information again, and the comparator circuit compares the read and inserted register information with the read and inserted register information. This provides any predefined overlap and indicates a comparison pair. The data formatter, which is coupled to the comparison circuit, responds to the comparison pair indication and synchronizes the reading and/or writing of the data set on the recording medium.

Claims (22)

1. Method for registering and synchronizing data sets on a recording medium, which has a pre-recorded servo pattern, and which is dependent on a continuous motion for reading and/or writing such data sets, which is interrupted by a stop at the end of the selected data set, tape rewind and restart, consisting of the following steps during such continuous motion of the recording medium while reading and/or writing data sets on the recording medium, reading and inserting (103,107) consecutive linear position register data is modulated within the pre-recorded servo pattern on the recording medium to provide the read and inserted linear position register message for such data set. Tape rewind and restart of such motion of the recording medium again, depending on the stop provided (134) the selected read and inserted linear position register message, reading and inserting (143,147) the pre-recorded linear position register data again, comparing (152) the read and inserted linear position register message. Insertion again as mentioned with the linear position registration information that is read and inserted as mentioned and the reference indication and synchronization (160) in response to such reference indication, reading and/or writing such data set on such recording medium. 2. The method described in Claim 1, whereby such pre-recorded linear position registration data is pre-recorded on at least two parallel servo patterns, and whereby such consecutive read and interpolation steps and repeated read and interpolation steps are performed on one of such parallel servo patterns and consist of the following additional steps: error detection in such consecutive read and interpolation steps on one of such parallel servo patterns, and substitution of such consecutive read and interpolation steps and reread and interpolation to the other parallel servo pattern when an error is detected. 3. The method described in Claim 2, whereby a pre-recorded servo pattern consists of a frame of groups of recursive pairs of state transitions and whereby the error detection procedure consists of identifying any missing or added state transitions from such pairs of state transitions. 4. The method described in Claim 2, where such servo pattern consists of a frame of a group of recursive pairs of transitions and such pre-modulated linear position register data which consists of a single bit of longitudinal position data with multiple bits in each frame of such recursive pairs of transitions and where such error detection procedure consists of identifying the undetected bits in one group of such transition pairs. 5. The method described in Claim 1, where such servo pattern consists of frames of alternating groups containing recursive pairs of state transitions and such pre-recorded, modulated linear position register data consisting of a single bit of longitudinal position data with multiple bits in each frame of such recursive pairs of state transitions, and where such sequential read and insertion procedures and such read and insertion procedures consist of reading such multi-bit longitudinal position data and counting each half-frame of each group of recursive pairs of state transitions starting from the first bit of such longitudinal position data to insert such linear position register data. 6. The method described in Claim 1, where the servo pattern consists of frames of alternating groups containing recursive pairs of state transitions, where the modulated pre-recorded linear position register data consists of synchronization characters followed by longitudinal position data, where each bit of the synchronization character and longitudinal position data consists of a single bit in each frame of the recursive pairs of state transitions, and where the successive read and insertion and the re-read and insertion steps consist of reading the synchronization character and longitudinal position data and counting each half-frame of the group of recursive pairs of state transitions, starting from the first bit of the synchronization character to insert the linear position register data. 7. The method described in Claim 1, whereby the data set is separated by a data separator, and whereby the synchronization procedure consists of synchronizing such read and/or write at the said data separator, followed immediately by the data set with the matched linear position register data. 8. The method described in Claim 1, where the medium for recording is magnetic tape, and where the servo pattern consists of a frame of alternating groups containing 4 and 5 pairs of recalled nonparallel magnetic transitions, where each bit of the modulated pre-recorded linear position register data contains at least one pair of modified magnetic transitions in one such group in each frame, and where the successive reads and insertions and the read and insertion procedures consist of reading such bits of the modulated pre-recorded linear position register data and counting the groups in each half-frame of the modulated pre-recorded linear position register data to insert the said linear position register data. 9. A data set synchronization registration system for a longitudinal recording medium containing a pre-recorded servo pattern. The recording medium is mounted on a tape drive unit (12) which controls the continuous movement of the recording medium for reading and/or writing data sets onto the medium, which is interrupted by a stop at the end of the selected data set, tape rewind of the drive unit, and the restart of the continuous movement of the medium for re-writing. The tape drive unit has a servo system (52) for reading the pre-recorded servo pattern onto the recording medium. A detector (102) is connected to the servo system for reading the pre-recorded linear position register data modulated within the servo pattern onto the recording medium during the movement of the recording medium. An interlearner (106) is used for interleaving the pre-recorded linear position register data. The detector and interlearner provide communication messages. A linear position register (120) is connected to the tape drive, to the detector, and to the interpupilla that responds to the tape drive stop, tape rewind, and the restart of the continuous motion to provide the selected read and interpupillary linear position register messages. A comparator (150) is connected to the detector, to the interpupilla, and to the logic that responds to the restart of the tape drive for the continuous motion of the recording medium to compare the read and interpupillary linear position register messages to the provided read and interpupillary linear position register messages and indicate the comparator. A data formatter (54) is connected to the comparator that responds to the comparator indication for synchronizing the reading and/or writing of the data set on the recording medium. 10. A system as described in Claim 9, whereby pre-recorded linear position registration data is pre-recorded on at least two parallel servo patterns, and also includes the following components: a switch coupled to such servo system and to such detector for supplying such pre-recorded linear position registration data from one of the two parallel servo patterns to such detector and for switching between such pre-recorded linear position registration data from the two parallel servo patterns; and an error detector coupled to such servo system and such switch for detecting errors in the pre-recorded linear position registration data supplied on one of the two parallel servo patterns and, upon detection of an error, the switch switches to the other parallel servo pattern. 11. The system, as described in Claim 10, consists of a pre-recorded servo pattern frame containing a group of recursive pairs of state transitions, and whereby error detectors identify missing or added state transitions to detect such errors. 12. The system as described in Claim 10, such servo pattern consists of a frame of groups of recursive pairs of transitions and pre-recorded linear position register data modulated as a single bit of longitudinal position data with multiple bits in each frame of such group of recursive pairs of transitions, and where such error detector identifies an undetected bit in one of the such groups of transition pairs to detect such error. 13. The system described in Claim 9, such servo pattern consists of frames of alternating groups of recursive transition pairs and pre-recorded linear position register data modulated as containing single bits of longitudinal position data with multiple bits in each frame of such recursive transition pairs, and such detector reads such multiple bits of longitudinal position data and such interpolator counts each half-frame in such group of recursive transition pairs, starting from the first bit of the longitudinal position data, to interpolate the linear position register data. 14. The system described in Claim 9, such servo pattern consists of a frame of alternating groups containing recursive pairs of transitions, where the modulated pre-recorded linear position register data consists of a synchronization character followed by longitudinal position data, where each bit of the synchronization character and longitudinal position data consists of a single bit in each frame of the recursive pairs of transitions, and where the detector reads the synchronization character and longitudinal position data, and the interpolator counts each half-frame in the group of recursive pairs of transitions, starting from the first bit of the synchronization character, to interpolate the linear position register data. 15. The system as specified in Claim 9, where such data is separated by a data separator, and where such data formatter synchronizes read and/or write operations at such data separator, immediately followed by a set of data where such linear position register data is matched. 16. The system as described in claim 9, where the recording medium is magnetic tape, and where the servo pattern consists of alternating group frames containing 4 and 5 non-parallel recursive pairs of magnetic transitions, where each bit of the modulated pre-recorded linear position register data contains at least one recursive pair of magnetic transitions in one such group in each frame, and where the detector reads such bits of the modulated pre-recorded linear position register data, and the interpolator counts each half-frame group of the modulated pre-recorded linear position register data to interpolate the linear position register data. 17. A magnetic tape medium containing pre-recorded, interplayable linear position register information recorded in a servo pattern of magnetic field transitions, which defines at least one longitudinal servo track consisting of a number of frames (73) of groups alternating according to the burst pattern (74,75), each group containing alternating numbers of at least two recursive pairs of non-parallel magnetic field tracks following servo transitions (80,81,82), at least one of these transitions of each pair is continuously longitudinally varying across the width of the track, at least two of these recursive pair transitions of the group in each frame are longitudinally adjusted by other transitions of the recursive pair transitions, and such adjusted transitions contain modulated linear position register information, and each such group contains interplay information. 18. The magnetic tap medium as specified in claim 17, where such servo pattern consists of alternating group frames containing 4 and 5 recursive pairs of transitions, and the transitions modified by the linear position register modulated in one group consist of a single bit of longitudinal position information with multiple bits in each such group frame containing recursive pairs of transitions. 19. A magnetic tape medium as specified in claim 17, consisting of two longitudinal servotracks, each containing a recorded servopattern of magnetic field transitions, with identical alternating groups of such transitions having identical recursive pairs of such transitions, having identical modulated linear position register data, and having identical interpolation data. 20. The magnetic tape medium as specified in claim 17, whereby information concerning the modulated linear position registration data shall also consist of synchronization characters followed by longitudinal position data. 21. A magnetic tape medium as specified in claim 20, where the longitudinal positional data consists of sequential, non-repeating messages, with a total length of the magnetic tape medium. 22. The magnetic tape medium as specified in claim 17, where each such frame of the Burst Pattern Alternatives group contains information about such insertion.