Abstract: A method and apparatus for improving optical disk recording performance is disclosed, which comprises reading data from an optical disk while writing data to the disk in order to verify the data, to control the power of the recording laser and to prevent overwriting of the disk.

Abstract: A vehicle data recording system has connections to one or more analog sensors, and stores data from the sensor(s) in a memory during laps of a track. The system provides for analog/digital conversion for converting analog data from the sensor(s) into digital data, and triggers a procedure for storing of the data in memory. Periods of storing of the data in memory are automatically started and stopped. The system stores in memory a set of data for a datum period and has means for storing further sets of data in a memory. A set of data stored during a first period is compared with a set of data stored during a further period and one of the sets of data is selected for retention in memory in accordance with a predetermined algorithm. The retained set of data is compared with the datum set and differences between the datum set and the selected set are output.