Copy protected disk

Claim 2

In a copy protected magnetic storage disk having a magnetic recording layer including a plurality of record tracks suitable for recording information-bearing data accompanied by a clock signal comprising a sequence of uniformly spaced pulses having a signal strength comparable to the signal strength of the information-bearing data, the clock signal being represented on a magnetic recording layer of a magnetic disk by a series of transitions that occur at the frequency of the clock signal pulses, the improvement comprising: (a) at least one of the record tracks including a control pattern of magnetic transitions, recorded at a predetermined location on the recording layer of the disk, representative of a code burst derived by temporarily changing the frequency of the pulses of the clock signal during a recording operation, the frequency of the transitions of the control pattern being beyond the frequency capability of an associated playback device, to cause, in response to the playing back of the control pattern, random playback data to be produced which are dissimilar from one playback operation to the next playback operation; (b) the recording layer including a plurality of radially arrayed sectors wherein the code burst follows a data sync gap in a predetermined recording track of one of said sectors; and (c) a serial number is encoded about the predetermined recording track following the code burst.

Claim 3

In a copy protected magnetic storage disk having a magnetic recording layer including a plurality of record track suitable for recording information-bearing data accompanied by a clock signal comprising a sequence of uniformly spaced pulses having a signal strength comparable to the signal strength of the information-bearing data, the clock signal being represented on a magnetic recording layer of a magnetic disk by a series of transitions that occur at the frequency of the clock pulses, the improvement comprising: (a) a plurality of control patterns of magnetic transitions, located at different but predetermined portions of at least one of the record tracks, each of the control patterns being representative of a code burst derived by temporarily changing the frequency of the pulses of the clock signal during a recording operation, the frequency of the transitions of each control pattern being beyond the frequency capability of an associated playback device to cause, in response to the playing back of each control pattern, random playback data to be produced which are dissimilar from one playback operation to the next playback operation; (b) the information-bearing data including a software program designed to sense the presence of each of the bursts by the random data generated therefrom, the software program further being designed to have one burst erased each time the program is run, whereby the bursts act as tickets allowing the program to run only a preselected number of times.

Claim 4

In a copy protected magnetic storage disk having a magnetic recording layer including a plurality of record track suitable for recording information-bearing data accompanied by a clock signal comprising a sequence of uniformly spaced pulses having a signal strength comparable to the signal strength of the information-bearing data, the clock signal being represented on a magnetic recording layer of a magnetic disk by a series of transitions that occur at the frequency of the clock pulses, the improvement comprising: (a) a plurality of control patterns of magnetic transitions, located at different but predetermined portions of at least one of the record tracks, each of the control patterns being representative of a code burst derived by temporarily changing the frequency of the pulses of the clock signal during a recording operation, the frequency of the transitions of each control pattern being beyond the frequency capability of an associated playback device to cause, in response to the playing back of each control pattern, random playback data to be produced which are dissimilar from one playback operation to the next playback operation; (b) the information-bearing data including a software program designed to sense the presence of each of the bursts by the random data generated therefrom, the software program further being designed to have one burst erased each time the program is run, whereby the bursts act as tickets allowing the program to run only a preselected number of times.

Claim 5

In a copy protected master disk having a magnetic recording layer including a plurality of record tracks suitable for recording information-bearing data accompanied by a standard clock signal comprised of a series of predetermined pulses having a signal strength comparable to the signal strength of the information-bearing data, the clock signal being represented on a recording layer of a magnetic disk by a series of transitions that occur at the frequency of the clock pulses, the improvement comprising: at least one of the record tracks including a control pattern of magnetic transitions, recorded at a predetermined location on the recording layer of the disk, representative of a code burst derived by temporarily changing the frequency of the standard clock signal during a recording operation, the frequency of the transitions of the control pattern causing, upon playback of said master disk, random playback data to be produced which are dissimilar from one playback operation to the next playback operation.

Claim 6

In a copy protected master disk having a magnetic recording layer including a plurality of record tracks suitable for recording information-bearing data accompanied by a standard clock signal comprised of a series of predetermined pulses having a signal strength comparable to the signal strength of the information-bearing data, the clock signal being represented on a recording layer of a magnetic disk by a series of transitions that occur at the frequency of the clock pulses, the improvement comprising: at least one of the record tracks including a control pattern of magnetic transitions, recorded at a predetermined location on the recording layer of the disk, representative of a code burst derived by temporarily changing the frequency of the standard clock signal during a recording operation, the frequency of the transitions of the control pattern causing, upon playback of said master disk, random playback data to be produced which are dissimilar from one playback operation to the next playback operation.

Claim 7

The master disk of claim 3 wherein, said recording layer is a flexible disk.

Claim 8

In a copy protected master disk having a magnetic recording layer including a plurality of record tracks suitable for recording information-bearing data accompanied by a signal comprising a train of uniformly spaced clock pulses having a signal strength comparable to the signal strength of the information-bearing data, the clock signal being represented on a magnetic recording layer of a magnetic disk by a series of transitions that occur at the frequency of the clock pulses, the improvement comprising: at least one of the record tracks comprising a recorded control pattern of relatively constant amplitude, at a predetermined location on the recording layer of the disk, representative of code burst derived by temporarily overriding a number of the clock pulses by producing a single, relatively long duration signal of substantially constant amplitude during a recording operation, the control pattern having an effective frequency characteristic that is less than the frequency response of an associated playback device, to cause random playback data to be produced which are dissimilar from one playback operation to the next playback operation.

Claim 9

In a copy protected master disk having a magnetic recording layer including a plurality of record tracks suitable for recording information-bearing data accompanied by a signal comprising a train of uniformly spaced clock pulses having a signal strength comparable to the signal strength of the information-bearing data, the clock signal being represented on a magnetic recording layer of a magnetic disk by a series of transitions that occur at the frequency of the clock pulses, the improvement comprising: at least one of the record tracks comprising a recorded control pattern of relatively constant amplitude, at a predetermined location on the recording layer of the disk, representative of code burst derived by temporarily overriding a number of the clock pulses by producing a single, relatively long duration signal of substantially constant amplitude during a recording operation, the control pattern having an effective frequency characteristic that is less than the frequency response of an associated playback device, to cause random playback data to be produced which are dissimilar from one playback operation to the next playback operation.

Claim 10

In a copy protected master disk having a magnetic recording layer including a plurality of record tracks suitable for recording information-bearing data accompanied by a standard block signal comprising a sequence of uniformly spaced pulses having a signal strength comparable to the signal strength of the information-bearing data, the clock signal being represented on a magnetic recording layer of a magnetic disk by a series of transitions that occur at the frequency of the clock pulses, the improvement comprising: at least one of the record tracks including a control pattern of magnetic transitions, recorded at a predetermined location on the recording layer of the disk, representative of a code burst derived by temporarily increasing the frequency of the pulses of the standard clock signal, the frequency of the transitions of the control pattern being greater than the frequency response of an associated playback device, to cause random magnetic playback impulses to be produced which are dissimilar from one playback operation to the next playback operation.

Claim 11

In a copy protected master disk having a magnetic recording layer including a plurality of record tracks suitable for recording information-bearing data accompanied by a standard block signal comprising a sequence of uniformly spaced pulses having a signal strength comparable to the signal strength of the information-bearing data, the clock signal being represented on a magnetic recording layer of a magnetic disk by a series of transitions that occur at the frequency of the clock pulses, the improvement comprising: at least one of the record tracks including a control pattern of magnetic transitions, recorded at a predetermined location on the recording layer of the disk, representative of a code burst derived by temporarily increasing the frequency of the pulses of the standard clock signal, the frequency of the transitions of the control pattern being greater than the frequency response of an associated playback device, to cause random magnetic playback impulses to be produced which are dissimilar from one playback operation to the next playback operation.