Information recording and reproducing device and method

摘要

A recording and reproducing device including a Viterbi decoder which improves address reading rate but has some amount of delay in decoding process, starts ALPC (Automatic Laser Power Control) operation by opening a write gate at the record start position of a sector, re-appraises recording suitability for the sector in question when the result of reading the last address of the sector comes out during the ALPC area, and terminates ALPC operation by closing the write gate at any point by the start of data recording area of the sector when the sector is not suitable for recording so as not to perform recording operation subsequently.