CD-ROM with machine-readable I.D. code

• US 5,541,904 A
• Filed: 06/02/1995
• Issued: 07/30/1996
• Est. Priority Date: 10/06/1993
• Status: Expired due to Term

• Current Assignee: Digital Audio Disc Corporation (Sony Group Corp.), Sony Corporation (Sony Group Corp.)
• Original Assignee: Digital Audio Disc Corporation (Sony Group Corp.), Sony Corporation (Sony Group Corp.)
• Inventors: Mitchell, Michael L., Kunz, Russ A., Brannon, Clifford R., Fite, Barry A.
• Primary Examiner(s): Epps, Georgia Y.
• Assistant Examiner(s): Edun, Muhammad N.
• Application Number:
  US08/458,476
• Time in Patent Office: 424 Days
• Field of Search: 369/58, 369/54, 369/53, 369/59, 369/32, 369/47, 369/48, 369/49, 369/275.5, 369/283, 369/286, 369/292, 369/275.2, 369/275.3
• US Class Current: 369/53.21
• CPC Class Codes: G06F 21/00 Security arrangements for protecting computers, components thereof, programs or data against unauthorised activity
• CPC Class Codes: G06K 1/126 by photographic or thermographic registration recording apparatus for measuring instruments G01D15/00
• CPC Class Codes: G06K 19/14 the marking being sensed by radiation
• CPC Class Codes: G11B 20/00086 Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 20/00115 wherein the record carrier stores a unique medium identifier
• CPC Class Codes: G11B 20/00123 the record carrier being identified by recognising some of its unique characteristics, e.g. a unique defect pattern serving as a physical signature of the record carrier
• CPC Class Codes: G11B 20/0021 involving encryption or decryption of contents recorded on or reproduced from a record carrier
• CPC Class Codes: G11B 20/00246 wherein the key is obtained from a local device, e.g. device key initially stored by the player or by the recorder
• CPC Class Codes: G11B 20/0026 the key being stored as a barcode
• CPC Class Codes: G11B 20/00326 the key being embossed on the record carrier
• CPC Class Codes: G11B 20/00557 wherein further management data is encrypted, e.g. sector headers, TOC or the lead-in or lead-out areas
• CPC Class Codes: G11B 20/00695 said measures preventing that data are read from the recording medium
• CPC Class Codes: G11B 20/00876 wherein physical copy protection means are attached to the medium, e.g. holograms, sensors, or additional semiconductor circuitry
• CPC Class Codes: G11B 20/00927 wherein said defects or errors are generated on purpose, e.g. intended scratches
• CPC Class Codes: G11B 23/281 by changing the physical properties of the record carrier
• CPC Class Codes: G11B 23/284 on the record carrier
• CPC Class Codes: G11B 23/36 Signals on record carriers or on containers and recorded by the same method as the main recording
• CPC Class Codes: G11B 23/38 Visual features other than those contained in record tracks or represented by sprocket holes the visual signals being auxiliary signals
• CPC Class Codes: G11B 27/105 of operating discs
• CPC Class Codes: G11B 27/24 by sensing features on the record carrier other than the transducing track ; sensing signals or marks recorded by another method than the main recording
• CPC Class Codes: G11B 7/0037 : with discs
• CPC Class Codes: G11B 7/005 : Reproducing G11B7/0065 takes precedence
• CPC Class Codes: G11B 7/24 : Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the arrangement of information on the carrier G11B7/007
• CPC Class Codes: G11B 7/26 : Apparatus or processes specially adapted for the manufacture of record carriers

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.

Claims

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.

2. A method according to claim 1, wherein said recording medium comprises a CD-ROM, and wherein said determining step and said assigning steps are performed using a CD-ROM drive interfaced to a personal computer into which said CD-ROM is inserted.

3. A method according to claim 1, wherein said defects comprise a plurality of predetermined defects intentionally formed onto said recording medium.