1. Field of the Invention
The present invention relates to a library device which mounts, stores, and retrieves multiple cartridges each containing a storage medium as well as accesses the storage medium.
2. Description of the Related Art
Conventionally, library devices are known which mount, store, and retrieve multiple cartridges each containing a storage medium such as a magnetic tape or optical disk as well as access the storage medium (e.g., Patent Documents 1, 2, and 3 as listed below).
These library devices have a cell array consisting of an array of multiple cells which contain multiple cartridges each containing a storage medium; media drives in which the cartridges are removably mounted and which accesses the storage medium contained in the cartridges; and a robot which transfers the cartridges between the cell array and the media drives.
With this type of library device, to transfer the cartridges between the cell array and the media drives reliably, the robot must be positioned accurately according to the location of a desired cell. For that, the location of the cell array is measured with high accuracy and the robot is positioned according to the resulting location information.
It takes considerable amounts of time and effort to obtain the location information, and thus the location information obtained must be stored safely.
For example, a magnetic-tape library device disclosed in Patent Document 1 stores control information including location information about individual magnetic tape cartridges in two separate non-volatile memories on a control board. This makes it possible, even if one of the non-volatile memories should be crashed or information in one of the non-volatile memories should be lost for some reason, to restore the magnetic-tape library device to working order using the information stored in the other non-volatile memory.
However, in the case of the magnetic-tape library device disclosed in Patent Document 1, when the existing control board is removed from the library device and a new one is mounted, such as when it becomes necessary to replace the control board for maintenance or the like, location information must be prepared anew by measuring the locations of all the cartridges. Thus, long hours of work and great cost are required to restore the library device to working order.
There are library devices which employ another method according to which important information such as location information about cartridges is backed up in a secondary storage medium such as a flexible disk and when the control board is changed, the operator manually restores the system using the information backed up in the storage medium. However, this method may cause trouble due to operating errors. Besides, it requires increased maintenance time.
[Patent Document 1]
Japanese Patent Laid-Open No. 06-168076 (pp. 1-2; FIGS. 6-8)
[Patent Document 2]
Japanese Patent Laid-Open No. 2002-117644 (pp. 1-2; FIGS. 1-3)
[Patent Document 3]
Japanese Patent Laid-Open No. 07-141124 (pp. 1-3; FIGS. 1-2)