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AssigneeTEAC Corporation
InventorsMitsumasa Kubo, Yuichi Sakamoto, Masashi Tanaka
Estimating the term…
CD-ROMS of poor quality, such as those having eccentric center holes or uneven weight distributions circumferentially, tend to overload b tracking and focusing servos and 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. The disk is first rotated at eight times the standard audio CD speed, with both tracking and focusing servo gains set at matching values. If then at least either servo malfunctions, the disk is of poor quality, fit for reading at four or two times the standard audio CD speed. If both servos function normally, on the other hand, then the disk quality is rechecked at the same speed as before but with the servo gains lowered six decibels. A malfunctioning of at least either servo at this time indicates that the disk is of intermediate quality, to be read at eight times the standard audio CD speed. On the other hand, if both servos still function normally, the disk Is of good quality, suitable for reading at 12 times the standard audio CD 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 variable gain tracking servo for holding the beam spot in alignment with a data track on the disk surface, and a variable gain 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.