CD-ROM with machine-readable I.D. code
First Claim
1. A method of reading a machine-readable code being formed of a first plurality of bits recorded in a corresponding plurality of recording areas on a recording medium, said method comprising the steps of:
- determining a plurality of defect count values corresponding to said plurality of recording areas, wherein each one of said plurality of defect count values corresponds to a number of defects present in a corresponding one of said plurality of recording areas;
assigning a first predetermined bit value to respective ones of said plurality of recording areas having a corresponding defect count value exceeding a predetermined threshold; and
assigning a second predetermined bit value to respective ones of said plurality of recording areas having a corresponding defect value less than said predetermined threshold, wherein said machine-readable code corresponds to the bit values assigned to said plurality of recording locations.
1 Assignment
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Accused Products
Abstract
A machine-readable serial number is formed on a CD-ROM by using a laser to selectively remove a reflective layer from the CD-ROM. Removal of the reflective layer creates defects in addressable information storage locations on the CD-ROM. The serial number is read by detecting the defects. The serial number is used in a software distribution system in which many different software programs are distributed on a single CD-ROM and an access code based on the desired software program and the serial number of a particular CD-ROM is used to "unlock" the desired program on the particular CD-ROM.
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Citations
3 Claims
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1. A method of reading a machine-readable code being formed of a first plurality of bits recorded in a corresponding plurality of recording areas on a recording medium, said method comprising the steps of:
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determining a plurality of defect count values corresponding to said plurality of recording areas, wherein each one of said plurality of defect count values corresponds to a number of defects present in a corresponding one of said plurality of recording areas; assigning a first predetermined bit value to respective ones of said plurality of recording areas having a corresponding defect count value exceeding a predetermined threshold; and assigning a second predetermined bit value to respective ones of said plurality of recording areas having a corresponding defect value less than said predetermined threshold, wherein said machine-readable code corresponds to the bit values assigned to said plurality of recording locations. - View Dependent Claims (2, 3)
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Specification