1. Field of the Invention
The field of the invention is data processing, or, more specifically, methods, apparatus, and products for reading data recorded on a recording medium having multiple tracks.
2. Description of Related Art
In recent years, tape media have more frequently been used as archives of photo data, video data, and the like. In this case, not only data (main data) itself but also metadata which is additional information of the data is important as data required to be stored for a long time. Here, conceivable metadata of photo data, for example, includes a place of shooting the photo, a date and time, an object of shooting, a person shooting the photo, equipment used for shooting, a recording format, a file name, a file size, and the like.
Since data and metadata are associated with each other as described above, it is preferable to process data and metadata together in execution of such processing as backup, archiving, or migration. This will be described by taking archiving in a tape medium as an example. Suppose a case where data and metadata are separately processed and archived in separate tape cartridges. In this case, in order to acquire information of data recorded on a certain tape cartridge, it is necessary to find the metadata of the data from a different tape cartridge. This increases costs to acquire the information. Thus, it is preferable to archive the data and the metadata together in the same tape cartridge.
Nevertheless, even if the data and the metadata are archived in the same cartridge, it is difficult to ensure that the data and the metadata are recorded in locations adjacent to each other in the tape cartridge. A tape medium is a sequential device and the metadata is added or deleted later. In consideration of these, apparently data cannot be recorded in a desired location on the tape medium. Accordingly, even if a pair or a combination of data and metadata is recorded on the same cartridge, the data and the metadata might be recorded in dispersed locations on the tape medium.
Meanwhile prior art techniques include replaying contents from a large-volume tape medium on which multiple contents are recorded. A title list of a tape medium is provided with a field for the number of contents, a field for a total time period, a genre field, and a content field. When a desired content is selected with a cursor from contents displayed in the content field, a start address of the selected content is read, so that video data of the content is reproduced.
In a case where data and metadata associated with each other are recorded in dispersed locations on the tape cartridge as described above, reading of a combination of all the data and metadata associated with each other from the tape cartridge requires repeated operations of reading necessary data after moving to a location where the data is recorded. That is, there has been a problem that multiple data elements cannot be read efficiently when these data elements to be read are recorded on the tape medium in a dispersed manner. Incidentally, the same problem can also be pointed out in a recording medium other than a tape medium, such as a magnetic disk.