| 摘要 |
PURPOSE:To move a head at a high speed by varying an alternate area position in a block depending on an initial defective sector distribution state. CONSTITUTION:Another area (alternate area) is variably set up in a position in the block where an average head moving process can be performed at the maximum speed in reference to the defective sector distribution state of each block from initial defective information recorded in advance on a medium, and in case of an encounter with a recording and reproducing infeasible area, the recording and reproducing are performed by shifting into the aforementioned area. That is, when the initial defective sector is '0', the medium is divided into (n) pieces of blocks, and the alternate area is provided in a center of each block against a defective sector of this block, and when the initial defective sector 11 is distributed in some part in high density, the alternate area is provided either before or behind the defective sector 11. By this method, the high speed alternate process if feasible. |
