Patent ID: 7120710

Claim:
A controller employed in a data recorder to control interruption and restart of recording data, wherein the data recorder records on a recording medium data stored in a buffer memory by emitting a laser beam against the recording medium, the laser beam being generated at a relatively high level or a relatively low level during a writing operation, wherein the laser beam at the relatively high power level forms a recording pit on a recording layer of the recording medium and the laser beam at the relatively low level does not form a recording pit on the recording layer of the recording medium, the controller comprising: a buffer underrun determination circuit for determining a buffer underrun warning state based on the amount of data stored in the buffer memory; a system control circuit for interrupting data recording only if the laser beam is generated at the relatively low power level, the system control circuit including: an address memory for storing at least one of an address of the recording medium and an address of the buffer memory when data recording on the recording medium is interrupted, each address indicating a location of data when the recording interruption occurred; a synchronizing circuit for sequentially reading the data recorded on the recording medium prior to the recording interruption and the data stored in the buffer memory prior to the recording interruption and synchronizing the recorded data and the stored data based on a synchronizing signal of a subcode; restart circuitry for restarting data recording on the recording medium based on the address stored in the address memory.