Abstract: A digital audio tape recorder is used as a digital data storage recorder and digital signals containing main data and sub-data are recorded in separate areas in each track of a plurality of tracks formed on a recording medium, wherein a predetermined number of tracks constitute a group and a plurality of groups are recorded on the medium. In the sub-area an identification signal is further recorded which indicates whether or not main data recorded in the main areas of a given group is same as the main data recorded in the main areas of preceding and subsequent adjacent groups. When identical data is multiply written for a plurality of units, a division of the multiply written portions is detected, and signal processing is facilitated.

Abstract: In this invention, a predetermined amount of data is given as one frame, and data having a predetermined format is recorded for each frame. A first area recording main data and a second area recording sub data are formed in each frame. Plural types of units each consisting of a plurality of frames are set, and a number of first units from a leading end of a recording medium and the numbers of other units from the leading end of the recording medium to a trailing end of the first units are recorded in the second area of a frame constituting the unit including the trailing end, thus facilitating a high-speed search operation.

Abstract: Data storage apparatus is known in which data is stored on a tape medium in at least two different longitudinally spaced sections (Partitions I and 0) with data recordal in each section being effected in accordance with a predetermined format. This format will generally be of the type in which tape-usage information is recorded in a system log (82) located upstream of the main data area (37). It is also known to record tape usage information relating to each tape section (Partition 1,0) in the system log (82) of that section. The present apparatus provides not only for the recording of usage information from which section-specific information can be derived, but also for the recording of aggregated tape usage information. This latter information is stored in the system log (82) of the first tape section (Partition 1) so as to be readily accessible upon tape loading.

Abstract: Before reading/writing a newly loaded data tape, it is known to carry out read/write tests on the tape drive concerned by using a section of the tape set aside for this purpose. This test section is generally marked off by formatting keys which must be accessed and read to identify the test section. In order to facilitate access to the test section, the disclosed data storage method locates the test section in the region of tape between a beginning-of-media BOM position and a beginning-of-recording BOR position with the latter being at a known distance from BOM. As a result, it is possible to rely simply on displacement measurement to access the test section from BOM. As a precaution, a check can be made for possible overshoot error in the tape positioning means so as to avoid testing being carried out beyond BOR.

Abstract: A method is disclosed for effecting update-in-place of data that has been recorded on tape in oblique tracks using a helical-scan recording technique. The data to be updated is recorded in a block of M tracks lying between first and second continuum each at least of N tracks where N is the worst-case number of tracks required to achieve head/track alignment. The block of M tracks comprises a first series of at least N tracks, a second series of tracks containing the data, and a third series of at least P tracks. When updating the data, the block is rewritten as a whole in a single continuum with the first track of the block being written within a distance of P tracks from the last track of the first continuum.

Abstract: A method of position detection on a recording medium is performed by moving the recording medium alternately in normal and reverse directions, while searching for a target position, and decreasing the travel speed of the recording medium with each change in direction. Immediately after a target position has been finally passed, a report signal of the search completion is generated, thereby shortening the search time.