Nippon Telegraph and Telephone Corporation

Hitachi, Ltd.

Ntt Data Communications Systems Corporation

Nippon T&t Corp.

Nobuyoshi Izawa

Masahiro Ueno

Michio Miyazaki

Takashi Doi

Kenji Tokumitsu

Yuji Yamane

Kikuji Katoh

Hiroki Arakawa

Masao Sakai

Yoshihiro Isomura

Kikuji Katou

Shigetaro Iwatsu

Yoshihiro Sako

Toru Takeda

A media library system capable of carrying out an access to each recording medium in very short time. A media exchange operation is controlled such that the storage cells of the storehouse are divided into at least two groups arranged in an order of average distances with respect to the media drive, including a first group with a shortest average distance with respect to the media drive, and when the previously used recording medium was mounted on the media drive from the first group, the previously used recording medium is stored in the first group, whereas when the previously used recording medium was mounted on the media drive from one group other than the first group, one recording medium with a lowest utilization frequency among an adjacent group of that one group having a shorter average distance with respect to the media drive than that one group is moved from that adjacent group to that one group and then the previously used recording medium is stored in that adjacent group.

Media library system using media management scheme for reducing

A media library system capable of reducing a time and an average moving distance of the media carrying unit required for exchanging the recording media. The system includes a storehouse having a plurality of storage cells for storing a plurality of recording media, a media driving unit for executing data read/write operation with respect to the recording media, and a media carrying unit for carrying the recording media between the storehouse and the media driving unit, so as to exchange a previously used recording medium mounted on the media driving unit with a new recording medium stored in the storehouse. The media exchange operation of the media carrying unit is controlled such that the storage cells of the storehouse are divided into at least two groups arranged in an order of average distances with respect to the media driving unit, including a first group with a shortest average distance with respect to the media driving unit and a last group with a longest average distance, and at least one vacant cell not storing any recording medium is secured among the storage cells of the first group after the media exchange operation is completed.

Media library system with improved media management scheme

A totally self-checking checker checks the faults of a logical circuit and also checks faults inside itself. The totally self-checking checker does not require a large number of gate circuits and minimizes the number of test code words that are used. The code words, of the code word sets to be used, are less than half of all the code words of code since the bits of code Y are divided into M disjoint partial sets.

Totally self-checking checker

Method for controlling information recording in an information recording apparatus which includes a rewritable information record medium containing a data record area having a plurality of data recording blocks and an alternative area in which data to be written into a defective block in the data record area is written, and writing and reading of data to and from the blocks and erasing of data may be carried out, wherein, data is written into the respective blocks in the data record area on the information record medium, and if a data record error is detected, data to be written into the defect block is written into a block of the alternative area. When data is subsequently rewritten, contents of all blocks in the data record area to be rewritten, including the block previously determined to be defective, are erased and the new data is rewritten, and the content of the alternative area is erased. If a data record error is detected after rewriting, the data to be written into the defect block is written into a block in the alternative area.

Information recording control system reusing a defective area

Growing community of inventors

Tokyo, Japan

Nobuyoshi Izawa