Abstract: By adjusting the advancement rate of an optical data storage medium in response to the amount of data to be written, and operating a laser with a minimum amount of write laser power level for the particular advancement rate to achieve a desired level of write effectiveness, data signals are written to the optical medium with a minimum amount of power. Where the optical medium comprises an optical disk, choosing the rate of disk rotation selectively establishes the advancement rate. Similarly, where the optical medium comprises an optical tape, choosing the rate of tape advancement from source reel to take-up reel selectively establishes the advancement rate. Preferably, the advancement rate is increased or decreased depending upon whether a greater or lesser quantity or write length of data resides in a write queue.

Abstract: A system to monitor write power calibration values in an optical drive to detect media and lens contamination, and take appropriate remedial action when contamination is found. A laser device writes data to an optical medium housed in the optical drive by imparting a laser beam upon the medium. The laser device provides the laser beam with a level of output power selected in accordance with a W/C value. A controller generates and repeatedly updates the W/C value, and provides it to the laser device. The controller samples the W/C value at selected times, and compares it to a predetermined value. If the W/C value exceeds the predetermined value, the controller executes a specific operational sequence. For example, the controller may issue a contamination warning. When the W/C value exceeds a second predetermined value, the controller may logically write-protect the optical medium, or shift the medium to another optical drive.

Abstract: Apparatus and method are provided to increase the capacity of spiral track data storage disks while improving the reliability of access to sectors on the disk. In one embodiment, employed when logical tracks on an optical disk are grouped into concentric bands, previously unusable sectors immediately following a band boundary can be reliably accessed. In accordance with this embodiment, when the target sector is, for example, the first sector of band N and a laser beam from a read head lands on a sector in the previous band N-1, the clock governing the data transfer rate is set to the frequency of the band N-1 and a sector in that band is detected and identified. Based upon the period of sectors in the band N-1, a delay interval is computed which ends when the last sector in the band N-1 rotates past the laser beam. Sector mark detection is disabled during the delay interval and the clock frequency changed to that of band N.

Abstract: The focus acquire system on optical disk recorder as well as other optical systems, signal processes a focus error signal FES to produce a modified FES which has a peak amplitude occurring closer to a desired focus position than the occurrence of peak amplitude of the FES. The modified FES also is signal processed to sharpen or slim the peak portion such that increasing the amplitude of the modified FES reaches an amplitude detection threshold closer to the true peak of the modified FES, and hence closer to the desired focus position than if the amplitude detection threshold were used on the FES. In a preferred form of the invention, FES is differentiated to produce a differentiated FES, then the differentiated FES is subtracted from FES to produce the modified FES.