Hardware key-on-disk system for copy-protecting magnetic storage media

A method of determining by a computer if a particular magnetic disk having tracks formed thereon which are divided into sectors is an original or a copy, with an original having indicia on at least one sector of at least one track thereon that are not modifiable by the disk write process, and a copy not having said indicia, or having indicia in a different pattern than said indicia, including a product program which is to be executed only if the disk is an original, and a disk test program stored performing said method to test if said particular disk is an original, said method comprising the steps of:

• writing at least portions of said tracks of said particular disk with a test pattern which generates a change in the pattern of magnetic domains in said disk at predetermined bit locations within said portions, said portions including at least said indicia-containing sectors, with a bit location in said sectors responding to said test pattern only in the absence of indicia thereon, to form a stored pattern in said portions;
• storing an expected pattern, which is indicative of the pattern which is expected to be read from said portions of an original disk including said indicia;
• comparing said expected pattern with said stored pattern on at least a per bit location basis, to determine if predetermined locations have the expected pattern of magnetic domains;
• and
• executing said product program only in response to the comparison determining that the predetermined locations have the expected pattern of magnetic domains, which is indicative of the presence of said indicia, thereby indicating that said particular disk is an original.

A method of determining by a computer if a particular magnetic tape having records formed thereon which are divided into tracks is an original or a copy, with an original having indicia on at least one track of at least one record that are not modifiable by the tape write process, and a copy not having said indicia, or having indicia in a different pattern than said indicia, including a product program, which is to be executed only if the tape is an original, and a tape test program for performing said method to test if said particular tape is an original, said method comprising the steps of:

• writing at least portions of said records of said particular tape with a test pattern which generates a change in the pattern of magnetic domains in said tape at predetermined bit locations within said portions, said portions including at least said indicia-containing tracks, with a bit location in said portions responding to said test pattern only in the absence of indicia thereon, to form a stored pattern in said portions;
• storing an expected pattern, which is indicative of the pattern which is expected to be read from said portions of an original tape including said indicia;
• comparing said expected pattern with said stored pattern on at least a per bit location basis, to determine if predetermined locations have the expected pattern of magnetic domains;
• and
• executing said product program only in response to the comparison determining that the predetermined locations have the expected pattern of magnetic domains, which is indicative of the presence of said indicia, thereby indicating that said particular tape is an original.

A method of determining by a computer if a particular magnetic disk having tracks formed thereon which are divided into sectors, with each sector being comprised of a plurality of bit storage locations, is an original or a copy, with an original disk having indicia on at least one bit storage location of at least one sector of at least one track that are not modifiable by the disk write process, with a copied disk not having said indicia, or having indicia in a different pattern than said indicia, including a product program, which is to be executed only if said disk is an original, and a disk test program for performing said method to test if said particular disk is an original, said method comprising the steps of:

• storing a key pattern, which is a binary representation of the presence or absence of said indicia at predetermined locations of said at least one track of an original disk;
• writing at least portions of said tracks of said particular disk with a test pattern which generates a change in the pattern of magnetic domains in said disk at predetermined bit locations within said portions, said portions including at least said indicia-containing bit storage locations, with a bit location in said portions responding to said test pattern only in the absence of indicia thereon, and reading out said portions to form a stored pattern, which is indicative of the presence or absence of said indicia at least at each bit storage location of said portions;
• comparing said test pattern with said stored pattern on at least a per bit location basis to determine if predetermined locations have a pattern of indicia, to provide a first compare result;
• comparing said key pattern with said first compare result on at least a per location basis to provide a second compare result which is indicative of whether or not said indicia on said sectors of said particular disk correspond with said indicia on said sectors of an original medium;
• and
• executing said product program only in response to the second compare result indicating a predetermined location comparison of said key pattern and said first compare result, thereby indicating that said particular disk is an original.

A software copy-protection apparatus, which is operable with a computer, comprising:

• a particular magnetic medium having tracks formed thereon which are divided into sectors, with each sector being comprised of a plurality of bit storage locations, with an original medium having indicia on at least one bit storage location of at least one sector of at least one track that are not modifiable by the medium write process, with a copied medium not having said indicia, or having indicia in a different pattern than said indicia;
• a product program which is to be executed only if said medium is an original;
• means for writing at least portions of said tracks with a test pattern which generates a change in the pattern of magnetic domains in said medium at predetermined bit locations within said portions, said portions including at least said indicia-containing bit locations, with a given bit location in said portions responding to said pattern only in the absence of indicia thereon;
• means for storing an expected pattern which is indicative of the pattern which is expected to be read from said portions of an original medium including indicia, in a first storage location;
• means for reading out said portions and storing the read out data in a second storage location;
• means for comparing the expected pattern stored in said first storage location with the data stored in said second storage location on at least a per bit corresponding storage location basis to determine if predetermined locations have the expected pattern of magnetic domains;
• and
• means responsive to the comparison for executing said product program only in response to the comparison determining that predetermined locations on the medium have the expected pattern of magnetic domains, which is indicative of the presence of said indicia, thereby indicating that said particular medium is an original.

A software copy-protection apparatus, which is operable with a computer, comprising:

• a particular magnetic medium having records formed thereon which are divided into tracks, with each track being comprised of a plurality of bit storage locations, with an original medium having indicia on at least one bit storage location of at least one track of at least one record that are not modifiable by the medium write process, with a copied medium not having said indicia, or having indicia in a different pattern than said indicia;
• a product program stored on said medium which is to be executed only if said medium is an original;
• means for writing at least portions of said records with a test pattern which generates a change in the pattern of magnetic domains in said medium at predetermined bit locations in said portions, said portions including at least said indicia-containing bit locations, with a given bit location in said portions responding to said test pattern only in the absence of indicia thereon;
• means for storing an expected pattern, which is indicative of the pattern which is expected to be read from said portions of an original medium including said indicia, in a first storage location;
• means for reading out said portions and storing the read out data in a second storage location;
• means for comparing the expected pattern stored in said first storage location with the data stored in said second storage location on a least a per bit corresponding basis to determine if predetermined locations have the expected pattern of magnetic domains;
• and
• means responsive to the comparison for executing said product program only in response to the comparison determining that predetermined locations exhibit the expected pattern of magnetic domains, which is indicative of the presence of said indicia, thereby indicating that said particular medium is an original.

A software copy-protection apparatus, which is operable with a computer, comprising:

• a particular magnetic medium having tracks formed thereon which are divided into sectors, with each sector being comprised of a plurality of bit storage locations, with an original medium having indicia on at least one bit storage location of at least one sector of at least one track that are not modifiable by the medium write process, with a copied medium not having said indicia, or having indicia in a different pattern than said indicia;
• a product program which is to be executed only if said medium is an original;
• means for storing a key pattern in a first storage location, which is a binary representation indicative of the presence or absence of said indicia at predetermined locations of said at least one track of an original medium;
• means for writing at least portions of said tracks of said medium with a test pattern which generates a change in the pattern of magnetic domains in said medium at predetermined bit locations within said portions, said portions including at least said indicia-containing bit storage location, with a bit location in said portions responding to said test pattern only in the absence of indicia thereon;
• means for storing said test pattern in a second storage location;
• means for reading out said portions and storing the read out data in a third storage location;
• means for comparing the test pattern stored in said second storage location with the data stored in said third storage location on at least a per bit corresponding storage location basis to provide a first compare result;
• means for comparing said key pattern, stored in said first storage location, with said first compare result on at least a per location basis to provide a second compare result which is indicative of whether or not said indicia on said sectors of said particular medium correspond with said indicia on said sectors of an original medium;
• and
• means responsive to the second compare result for executing said product program only in response to the comparison determining that predetermined locations on the medium and the key pattern indicate a predetermined location comparison, thereby indicating that said particular medium is an original.

A software copy-protection apparatus, which is operable with a computer, comprising:

• a particular magnetic medium having records formed thereon which are divided into tracks, with each track being comprised of a plurality of bit storage locations, with an original medium having indicia on at least one bit storage location of at least one track of at least one record that are not modifiable by the medium write process, with a copied medium not having said indicia, or having indicia in a different pattern than said indicia;
• a product program which is to be executed only if said medium is an original;
• means for storing a key pattern in a first storage location, which is a binary representation indicative of the presence or absence of said indicia at predetermined locations of said at least one track of an original medium;
• means for writing at least portions of said records of said medium with a test pattern which generates a change in the pattern of magnetic domains in said medium at predetermined bit locations within said portions, said portions including at least said indicia-containing bit storage locations, with a bit location in said portions responding to said test pattern only in the absence of indicia thereon;
• means for storing said test pattern in a second storage location;
• means for reading out said portions and storing the read out data in a third storage location;
• means for comparing the test pattern stored in said second storage location with the data stored in said third storage location on at least a per bit corresponding storage location basis to provide a first compare result;
• means for comparing said key pattern, stored in said first storage location, with said first compare result on at least a per location basis to provide a second compare result which is indicative of whether or not said indicia on said tracks of said particular medium correspond with said indicia on said tracks of an original medium;
• and
• means responsive to the second compare result for executing said product program only in response to the comparison determining that predetermined locations on the medium and the key pattern indicate a predetermined location comparison, thereby indicating that said particular medium is an original.