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AssigneeTEAC Corporation
InventorsMitsumasa Kubo, Yuichi Sakamoto, Masashi Tanaka
Estimating the term…
CD-ROMS of more or less poor quality, such as those having eccentric center holes or uneven weight distributions circumferentially, tend to overload tracking and focusing servos and hence to invite read errors and retries. Each CD-ROM on being loaded into a CD-ROM drive is therefore checked as to its quality preparatory to reading. Either or both of the servos may fail to keep the read beam under control if the disk is not of good quality. Such unlocking of either or both servos is detected in terms of the number of transducer output pulses, the magnitude of transducer output voltage, or the number of read errors, during a complete disk revolution. Disk quality is first checked at four times the standard audio CD speed, then at eight times that speed, and finally at twelve times that speed. Disks of poor quality are read at two times the standard audio CD speed, those of below-average quality at four times that speed, those of above-average quality at eight times that speed, and those of good quality at twelve times that speed.
In an apparatus for data recovery from rotating data storage disks of varying physical qualities, the apparatus having a transducer for reading a disk by irradiating the same with a beam of light, a tracking servo for holding the beam spot in alignment with a data track on the disk surface, and a focusing servo for holding the beam focused on the disk surface, a method comprising the steps of:
In an apparatus for data recovery from rotating data storage disks of varying physical qualities, the apparatus having a transducer for reading a disk by irradiating the same with a beam of light, a tracking servo for holding the beam spot in alignment with a data track on the disk surface, and a focusing servo for holding the beam focused on the disk surface, a method comprising the steps of:
An apparatus for data recovery from rotating data storage disks of varying physical qualities, each disk having data prerecorded thereon along a multiturn track, wherein the improvement resides in the combination of:
Dependencies are inferred from the claim text.