JPH0563861B

Disclosed is a control method for writing or reading sequentially a plurality of blocks of data for a storage device using a recording medium, such as a photo disk, with a number of recording blocks each having a unique address. In writing data, a plurality of data blocks to be written concurrently are given in their pointer fields the first address indicating the same alternative block, and these data are written in consecutive recording blocks on the recording medium. If blocks with write errors are detected, the data blocks corresponding to the error blocks are written sequentially in an alternative area starting from the first address, after replacing the pointer fields with the second address indicating the defective blocks, respectively. This allows the access of the alternative blocks for defective blocks by detecting the pointer address within the pointer fields of normal blocks preceding and following each of the defective blocks during the data reading operation.