Abstract: The present invention relates to a method of copy protecting optical discs, such as CDs or DVDs. Instead of encoding data onto the CD-ROMs in a conventional manner which ensures balanced dc content, for copy protection the digital data is encoded and recorded onto the optical disc such that it is arranged to give some of the recorded digital data highly unbalanced dc content. Thus, for example, the DSV (digital sum value) value of the encoded data is recorded so that the DSV value changes continuously once 50 frames of data or more.

Abstract: The invention provides a device driver for monitoring and controlling access to data on a computer readable medium. The device driver comprises an interface for access to a device-driver stack for a media drive, a detector for detecting the insertion of a computer readable medium in said media drive, and a monitor for monitoring data transfer from said computer readable medium. The monitor evaluates a behavior characteristic of an application accessing data on said computer readable medium, and indicates when said behavior characteristic fulfills predetermined criteria. A control system is responsive to said monitor for issuing at least one control output when said behavior characteristic fulfills said predetermined criteria. The invention also provides a method of monitoring and controlling access to data on a computer readable medium by means of the device driver.

Abstract: The present invention relates to a method of copy protecting optical discs, such as CDs or DVDs. Instead of encoding data onto the CD-ROMs in a conventional manner which ensures balanced dc content, for copy protection the digital data is encoded and recorded onto the optical disc such that it is arranged to give some of the recorded digital data highly unbalanced dc content. Thus, for example, the DSV (digital sum value) value of the encoded data is recorded so that the DSV value changes continuously once 50 frames of data or more.

Abstract: The present invention relates to a method of copy protecting optical discs, such as CD-ROMs. Instead of encoding data onto the CD-ROMs in a manner which ensures balanced dc content, for copy protection the digital data is encoded and recorded onto the optical disc such that it is arranged to give some of the recorded digital data unbalanced dc content. Thus, for example, the DSV value of the encoded data may be changed rapidly in less than (100) frames to (FIG. 9). For an area of digital data on the optical disc in which the DSV has been caused to rise steeply (FIG. 10a), heavy distortions in audio arise (FIG. 10c) during an attempt to copy an audio track including the single segment of unbalanced dc content.

Abstract: Conventionally, multiple session discs are provided with backward going pointers (P). It is now disclosed that it is possible to navigate a multiple session disc without the provision of such pointers (P). A multiple session optical disc which also acts to copy protect audio data has a first audio session (40) and a second data session (60). The data session (60) has a Lead-In (LI), a program area (32), and a Lead-Out (LO). It also has a primary volume descriptor (50) containing control data identifying the files within the data session but there is no pointer from the Lead-Out (LO) of the session (60) to any part of the program area (32). The audio session (40) has a program area (32) extending between the Lead-in (LI) and the Lead-Out (LO). To copy protect the audio information, the audio data (40) is hidden from a data reader. For example, the Lead-In (LI) to the audio session (40) and the Lead-In (LI) to the data session (60) may each erroneously identify the data in the audio session as data.

Abstract: The invention provides a device driver for monitoring and controlling access to data on a computer readable medium. The device driver comprises an interface for access to a device-driver stack for a media drive, a detector for detecting the insertion of a computer readable medium in said media drive, and a monitor for monitoring data transfer from said computer readable medium. The monitor evaluates a behaviour characteristic of an application accessing data on said computer readable medium, and indicates when said behaviour characteristic fulfills predetermined criteria. A control system is responsive to said monitor for issuing at least one control output when said behaviour characteristic fulfills said predetermined criteria. The invention also provides a method of monitoring and controlling access to data on a computer readable medium by means of the device driver.

Abstract: According to one standard, a multiple session audio disc has only two sessions, namely an audio session including successive audio tracks, and a following data session including just one data track. It has been determined that where copying of such a disc is to be undertaken using several common Microsoft Windows operating systems, the disc can be copy protected by breaching the rules of this standard. Specifically, if a two session audio disc is provided which has two tracks in the second data session, the Windows NT, Windows 2000 and Windows XP operating systems will fail to reconcile the data on the disc. As the operating systems are prevented from copying the audio information on the disc the use of the non-standard format acts to copy protect the optical disc.

Abstract: A copy protected optical disc has a first audio session and a second data session. The second data session has the conventional structure of a Lead-In, a program area, and a Lead-Out, and the information in the Lead-In area of the second session is altered to provide copy protection for the audio content on the disc. For example, the TOC of the second session has had the content at frames N+12, N+13 and N+14 indicated as an audio track by the setting of CONTROL to 0. This is equivalent to providing a pointer which is said to address an audio track but which points to an area of the program area at which there is no audio track. When reading data from an optical disc a user will use an application player to access the optical disc by an appropriate driver. Where the information on the disc is interpreted by a CD file system program CDFS.