EP0172439A2
Expired / Lapsed
EP
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Copy protected disk
Assignee: Verbatim Corp
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Filing: 1985-07-25
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Granted: —
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Expires: 2005-07-25
Abstract
Abstract A copy protected and serialized magnetic information storage medium. The medium includes a specially encoded "burst" having an abnormal pattern of transitions to cause the read circuitry to drift and thereby generate a random number. The burst is typically located within a sector near the beginning of the data field. A serial number follows the burst and a verification of the presence of the burst also verifies the integrity of the serial number. Duplicate readings of the burst confirm the the status of the medium as an original by a comparing the data patterns produced. The code burst can also be used in conjunction with appropriate software as a ticket, allowing only a preselected number of plays, then disenabling the software. The burst may be utilized with either hard or flexible disk storage media.
Inventors
- 👤 Charles R. Bond
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 14:19
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/00086; G11B20/00731; G11B20/00746; G11B20/00094; G11B20/0021; G11B20/00572; G11B20/00586; G11B20/0071; G11B20/00818
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
64 words
A copy protected magnetic information storage medium comprising: a substrate having at least one magnetic recording layer suitable for recording in a plurality of data tracks; and a code burst comprising a sequence of nonstandard code recorded at nominal signal strength, and adapted to be nonrecoverable by a computer read circuit, the code burst being located on at least one of said data tracks.
Claim 2
Dependent Claim
64 words
A copy protected magnetic information storage medium comprising: a substrate having at least one magnetic recording layer suitable for recording in a plurality of data tracks; and a code burst comprising a sequence of nonstandard code recorded at nominal signal strength, and adapted to be nonrecoverable by a computer read circuit, the code burst being located on at least one of said data tracks.
Claim 3
Dependent Claim
36 words
The magnetic information storage medium of claim 1 wherein, the code burst comprises a code written by altering a clock frequency to produce clocking signals which are beyond the ability of said read circuit to distinguish.
Claim 4
Dependent Claim
21 words
The magnetic information storage medium of claim 2 wherein, said clock frequency is approximately one tenth of a nominal clock frequency.
Claim 5
Dependent Claim
33 words
The magnetic information storage medium of claim 1 wherein, the code burst comprises a code written by utilizing a direct current erase over a portion of said data track comprising the code burst.
Claim 6
Dependent Claim
46 words
The magnetic information storage medium of claim 1 wherein, the substrate includes a plurality of radially arrayed sectors and the code burst follows a data sync gap in one of said sectors; and a serial number is encoded about the recording track following the code burst.
Claim 7
Dependent Claim
83 words
The magnetic information storage medium of claim 1, and further including, a plurality of code bursts, located about different portions of the recording tracks, the bursts being adapted for use with a software program designed to sense the presence of the bursts by a random data pattern generated therefrom, the software further being adapted to erase at least one burst each time said program is run, whereby said bursts act as tickets allowing said program to run only a preselected number of times.
Claim 8
Dependent Claim
15 words
The magnetic information storage medium of claim 1 wherein, said substrate is a flexible disk.
Claim 9
Independent Claim
59 words
A method for producing a flexible magnetic information storage medium, having an uncopyable magnetic signature, comprising: recording at least one code burst about a recording track of the medium, the code burst comprising a segment of abnormal transitions which cannot be recovered by a data recovery circuit, said abnormal transitions resulting in random data when read by said circuit.
Claim 10
Independent Claim
59 words
A method for producing a flexible magnetic information storage medium, having an uncopyable magnetic signature, comprising: recording at least one code burst about a recording track of the medium, the code burst comprising a segment of abnormal transitions which cannot be recovered by a data recovery circuit, said abnormal transitions resulting in random data when read by said circuit.
Claim 11
Dependent Claim
17 words
The method of claim 8, wherein, the code burst is produced by altering a normal clock signal.
Claim 12
Dependent Claim
18 words
The method of claim 8, wherein, the code burst is produced by generating a direct current erase signal.
Claim 13
Dependent Claim
22 words
The method of claim 8, and further including, a serial number encoded following the code burst for positive identification of the medium.
References Cited (Backward Citations)
No citation records indexed.
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