Patent ID: 7236436

Claim:
A controller for controlling interruption and restarting data writing to a recording medium, wherein writing the data stored in a buffer memory to the recording medium or reading the written data from the recording medium is performed by selectively providing an optical head performing a laser irradiation with a write laser power source or a read laser power source, the controller comprising: an address memory for storing at least one of an address of the recording medium and an address of the buffer memory when the writing of data to the recording medium is interrupted, each address indicating a location where the writing interruption occurred; and a restart circuit for generating an instruction for restarting the writing of data to the recording medium by changing the power source provided to the optical head from the read laser power source to the write laser power source based on the address stored in the address memory while reading the written data from the recording medium by providing the optical head with the read laser power source, wherein the restart circuit generates an instruction for setting the voltage of the write laser power source to a write level prior to generating the instruction for restarting.