Method and apparatus for positioning a magnetic head in a magnetic layer memory system using tracking by reading a spaced pair of corresponding subtracks

Claim 1

A method for positioning a magnetic head with reference to a center of a recorded track and reading information from the recorded track, comprising the steps of: providing the recorded track as two sub-tracks of equal width with a narrow space therebetween, each of the sub-tracks having a same information signal recorded thereon; providing the magnetic head with a write head divided into two equal width sub-heads, a width of each of the sub-heads being the same as a width of each of the sub-tracks, and a gap between the two write sub-heads being the same as said narrow space, and also providing said same magnetic head with a read head formed of two sub-heads each of which have a width which is less than a width of each of said sub-tracks and said write sub-heads and which are spaced apart from one another at a gap therebetween which is less than said narrow space between said sub-tracks, said read sub-heads and said write sub-heads being aligned relative to one another such that the gaps between the sub-heads are in alignment over a center of said narrow space between the sub-tracks when the sub-heads are positioned over the sub-tracks; reading the information signal on the sub-tracks by combining outputs from both of the read sub-heads and outputting said information signal based on the combined outputs; and when reading the information, centering a middle of the gap between the two read sub-heads above a center of said narrow space between the sub-tracks by comparing read signals from each of the read sub-heads and moving the head relative to the two sub-tracks until the read signals are equal, the read signal from one of the read sub-heads increasing and the read signal from the other read sub-head decreasing as soon as the center of the gap between the read sub-heads is displaced from the center of the narrow space between the sub-tracks.

Claim 2

A method for positioning a magnetic head with reference to a center of a recorded track and reading information from the recorded track, comprising the steps of: providing the recorded track as two sub-tracks of equal width with a narrow space therebetween, each of the sub-tracks having a same information signal recorded thereon; providing the magnetic head with a write head divided into two equal width sub-heads, a width of each of the sub-heads being the same as a width of each of the sub-tracks, and a gap between the two write sub-heads being the same as said narrow space, and also providing said same magnetic head with a read head formed of two sub-heads each of which have a width which is less than a width of each of said sub-tracks and said write sub-heads and which are spaced apart from one another at a gap therebetween which is less than said narrow space between said sub-tracks, said read sub-heads and said write sub-heads being aligned relative to one another such that the gaps between the sub-heads are in alignment over a center of said narrow space between the sub-tracks when the sub-heads are positioned over the sub-tracks; reading the information signal on the sub-tracks by combining outputs from both of the read sub-heads and outputting said information signal based on the combined outputs; and when reading the information, centering a middle of the gap between the two read sub-heads above a center of said narrow space between the sub-tracks by comparing read signals from each of the read sub-heads and moving the head relative to the two sub-tracks until the read signals are equal, the read signal from one of the read sub-heads increasing and the read signal from the other read sub-head decreasing as soon as the center of the gap between the read sub-heads is displaced from the center of the narrow space between the sub-tracks.

Claim 4

A method for positioning a magnetic head with reference to a center of a recorded track and reading information from the recorded track, comprising the steps of: providing the recorded track as two sub-tracks of equal width with a narrow space therebetween; providing the magnetic head with a write head divided into two equal width sub-heads, a width of each of the sub-heads being the same as a width of each of the sub-tracks, and a gap between the two write sub-heads being the same as said narrow space, and also providing said same magnetic head with a read head formed of two sub-heads each of which have a width which is less than a width of each of said sub-tracks and said write sub-heads and which are spaced apart from one another at a gap therebetween which is less than said narrow space between said sub-tracks, said read sub-heads and said write sub-heads being aligned relative to one another such that the gaps between the sub-heads are in alignment over a center of said narrow space between the sub-tracks when the sub-heads are positioned over the sub-tracks; and when reading the information, centering a middle of the gap between the two read sub-heads above a center of said narrow space between the sub-tracks by comparing read signals from each of the read sub-heads and moving the head relative to the two sub-tracks until the read signals are equal, the read signal from one of the read sub-heads increasing and the read signal from the other read sub-head decreasing as soon as the center of the gap between the read sub-heads is displaced from the center of the narrow space between the sub-tracks.

Claim 5

A method for positioning a magnetic head with reference to a center of a recorded track and reading information from the recorded track, comprising the steps of: providing the recorded track as two sub-tracks of equal width with a narrow space therebetween; providing the magnetic head with a write head divided into two equal width sub-heads, a width of each of the sub-heads being the same as a width of each of the sub-tracks, and a gap between the two write sub-heads being the same as said narrow space, and also providing said same magnetic head with a read head formed of two sub-heads each of which have a width which is less than a width of each of said sub-tracks and said write sub-heads and which are spaced apart from one another at a gap therebetween which is less than said narrow space between said sub-tracks, said read sub-heads and said write sub-heads being aligned relative to one another such that the gaps between the sub-heads are in alignment over a center of said narrow space between the sub-tracks when the sub-heads are positioned over the sub-tracks; and when reading the information, centering a middle of the gap between the two read sub-heads above a center of said narrow space between the sub-tracks by comparing read signals from each of the read sub-heads and moving the head relative to the two sub-tracks until the read signals are equal, the read signal from one of the read sub-heads increasing and the read signal from the other read sub-head decreasing as soon as the center of the gap between the read sub-heads is displaced from the center of the narrow space between the sub-tracks.

Claim 7

A method for positioning a magnetic head with reference to a center of a recorded track and reading information from the recorded track, comprising the steps of: providing the recorded track as two subt5-racks of equal width with a narrow space therebetween, each of the sub-tracks having a same information recorded thereon; providing the magnetic head with a write head divided into two equal width sub-heads, a width of each of the sub-heads being the same as a width of each of the sub-tracks, and a gap between the two write sub-heads being the same as said narrow space, and also providing said same magnetic head with a read head formed of two sub-heads each of which have a width which is less than a width of each of said sub-tracks and said write sub-heads and which are spaced apart from one another at a gap therebetween, said read sub-heads and said write sub-heads being aligned relative to one another such that the gaps between the sub-heads are in alignment over a center of said narrow space between the sub-tracks when the sub-heads are positioned over the sub-tracks; reading the information signal on the sub-tracks by combining outputs from both of the read sub-heads and outputting said information signal based on the combined outputs; and when reading the information, centering a middle of the gap between the two read sub-heads above a center of said narrow space between the sub-tracks by comparing read signals from each of the read sub-heads and moving the head relative to the two sub-tracks until the read signals are equal, the read signal from one of the read sub-heads increasing and the read signal from the other read sub-head decreasing when the center of the gap between the read sub-heads is displaced from the center of the narrow space between the sub-tracks.

Claim 8

A method for positioning a magnetic head with reference to a center of a recorded track and reading information from the recorded track, comprising the steps of: providing the recorded track as two subt5-racks of equal width with a narrow space therebetween, each of the sub-tracks having a same information recorded thereon; providing the magnetic head with a write head divided into two equal width sub-heads, a width of each of the sub-heads being the same as a width of each of the sub-tracks, and a gap between the two write sub-heads being the same as said narrow space, and also providing said same magnetic head with a read head formed of two sub-heads each of which have a width which is less than a width of each of said sub-tracks and said write sub-heads and which are spaced apart from one another at a gap therebetween, said read sub-heads and said write sub-heads being aligned relative to one another such that the gaps between the sub-heads are in alignment over a center of said narrow space between the sub-tracks when the sub-heads are positioned over the sub-tracks; reading the information signal on the sub-tracks by combining outputs from both of the read sub-heads and outputting said information signal based on the combined outputs; and when reading the information, centering a middle of the gap between the two read sub-heads above a center of said narrow space between the sub-tracks by comparing read signals from each of the read sub-heads and moving the head relative to the two sub-tracks until the read signals are equal, the read signal from one of the read sub-heads increasing and the read signal from the other read sub-head decreasing when the center of the gap between the read sub-heads is displaced from the center of the narrow space between the sub-tracks.

Claim 10

A system for positioning a magnetic head with reference to a center of a recorded track and reading information from the recorded track, comprising: the recorded track being provided as two sub-tracks of equal width with a narrow space therebetween, each of the sub-tracks having a same information signal recorded thereon; the magnetic head having a write head divided into two equal width sub-heads, a width of each of the sub-heads being the same as a width of each of the sub-tracks, and a gap between the two write sub-heads being the same as said narrow space, and said same magnetic head also having a read head formed of two sub-heads each of which have a width which is less than a width of each of said sub-tracks and said write sub-heads and which are spaced apart from one another at a gap therebetween which is less than said narrow space between said sub-tracks, said read sub-heads and said write sub-heads being aligned relative to one another such that the gaps between the sub-heads are in alignment over a center of said narrow space between the sub-tracks when the sub-heads are positioned over the sub-tracks; means for reading the information signal on the sub-tracks by combining outputs from both of the read sub-heads and outputting said information signal based on the combined outputs; and means for centering a middle of the gap between the two read sub-heads above a center of said narrow space between the sub-tracks by comparing read signals from each of the read sub-heads and moving the head relative to the two sub-tracks until the read signals are equal, the read signal from one of the read sub-heads increasing and the read signal from the other read sub-head decreasing as soon as the center of the gap between the read sub-heads is displaced from the center of the narrow space between the sub-tracks.

Claim 11

A system for positioning a magnetic head with reference to a center of a recorded track and reading information from the recorded track, comprising: the recorded track being provided as two sub-tracks of equal width with a narrow space therebetween, each of the sub-tracks having a same information signal recorded thereon; the magnetic head having a write head divided into two equal width sub-heads, a width of each of the sub-heads being the same as a width of each of the sub-tracks, and a gap between the two write sub-heads being the same as said narrow space, and said same magnetic head also having a read head formed of two sub-heads each of which have a width which is less than a width of each of said sub-tracks and said write sub-heads and which are spaced apart from one another at a gap therebetween which is less than said narrow space between said sub-tracks, said read sub-heads and said write sub-heads being aligned relative to one another such that the gaps between the sub-heads are in alignment over a center of said narrow space between the sub-tracks when the sub-heads are positioned over the sub-tracks; means for reading the information signal on the sub-tracks by combining outputs from both of the read sub-heads and outputting said information signal based on the combined outputs; and means for centering a middle of the gap between the two read sub-heads above a center of said narrow space between the sub-tracks by comparing read signals from each of the read sub-heads and moving the head relative to the two sub-tracks until the read signals are equal, the read signal from one of the read sub-heads increasing and the read signal from the other read sub-head decreasing as soon as the center of the gap between the read sub-heads is displaced from the center of the narrow space between the sub-tracks.