Servo method and apparatus for very high track density magnetic recording by adjusting head position based on servo information read from adjacent track

A method of linear recording on a magnetic medium comprising:

• writing information in a first track lengthwise on the magnetic medium, the first track being written to include data and alternate even and odd servo blocks;
• writing information in a second track upon completion of the first track, the second track being written in adjacent lateral relationship to the first track;
• monitoring the first track during writing of the second track for the presence of an odd servo block;
• interrupting the writing of information in the second track when an odd servo block is sensed in the first track;
• reading the amplitude of the odd servo block;
• resuming writing information in the second track;
• monitoring the first track during writing of the second track for the presence of an even servo block;
• reading the amplitude of the even servo block;
• supplying a reference differential indicating a predetermined lateral relationship between tracks;
• comparing the difference between the even and odd servo block amplitude readings with the reference differential;
• adjusting the lateral position of writing in the second track in response to the comparison when said comparison falls outside the reference differential to bring the two tracks into the predetermined lateral relationship.

Apparatus for linear recording on a magnetic medium comprising:

• means for writing information in a first track lengthwise on a magnetic medium, the first track being written to include alternate data and servo information;
• means for writing information in a second track upon completion of the first track, the second track being written in adjacent lateral relationship to the first track;
• means for monitoring the first track during writing of the second track for the presence of servo information;
• means for interrupting the writing of information in the second track when a servo block is sensed in the first track;
• means for reading the amplitude of servo information;
• means for resuming writing information in the second track;
• means for reading the amplitude of additional servo information in the first track;
• means for supplying a reference differential indicating a predetermined lateral relationship between tracks;
• means for comparing the difference between the two amplitude readings of servo information with the reference differential;
• means for adjusting the lateral position of writing in the second track in response to the comparison when said comparison falls outside the reference differential to bring the two tracks into the predetermined lateral relationship.

Apparatus for linear recording on a magnetic medium comprising:

• means for writing information in a first track lengthwise on a magnetic medium, the first track being written to include data and alternate even and odd servo blocks;
• means for writing information in a second track upon completion of the first track, the second track being written in adjacent lateral relationship to the first track;
• means for monitoring the first track during writing of the second track for the presence of an odd servo block;
• means for interrupting the writing of information in the second track when an odd servo block is sensed in the first track;
• means for reading the amplitude of the odd servo block;
• means for resuming writing information in the second track;
• means for monitoring the first track during writing of the second track for the presence of an even servo block;
• means for reading the amplitude of the even servo block;
• means for supplying a reference differential indicating a predetermined lateral relationship between tracks;
• means for comparing the difference between the even and odd servo block amplitude readings with the reference differential;
• adjusting the lateral position of writing in the second track in response to the comparison when said comparison falls outside the reference differential to bring the two tracks into the predetermined lateral relationship.

A method of linear recording on a magnetic tape comprising:

• writing information in a first track lengthwise on the magnetic tape, the first track being written at an azimuth angle to include data and alternate even and odd servo blocks;
• writing information in a second track upon completion of the first track, the second track being written at a different azimuth angle and in adjacent lateral relationship to the first track;
• monitoring the first track during writing of the second track for the presence of an odd servo block;
• interrupting the writing of information in the second track when an odd servo block is sensed in the first track;
• reading the amplitude of the odd servo block;
• resuming writing information in the second track;
• monitoring the first track during writing of the second track for the presence of an even servo block;
• reading the amplitude of the even servo block;
• supplying a reference differential indicating that the first and second tracks are substantially contiguous;
• comparing the difference between the even and odd servo block amplitude readings with the reference differential;
• moving the lateral position of writing of the second track further from said first track when said difference is greater than said differential;
• moving the lateral position of writing of the second track toward said first track when said difference is less than said differential.

Apparatus for linear recording on a magnetic tape comprising:

• means for writing information in a first track lengthwise on a magnetic tape, the first track being written at an azimuth angle to include data and alternate even and odd servo blocks;
• means for writing information in a second track upon completion of the first track, the second track being written at a different azimuth angle and in adjacent lateral relationship to the first track;
• means for monitoring the first track during writing of the second track for the presence of an odd servo block;
• means for interrupting the writing of information in the second track when an odd servo block is sensed in the first track;
• means for reading the amplitude of the odd servo block;
• means for resuming writing information in the second track;
• means for monitoring the first track during writing of the second track for the presence of an even servo block;
• means for reading the amplitude of the even servo block;
• means for supplying a reference differential that the first and second tracks are substantially contiguous;
• means for comparing the difference between the even and odd servo block amplitude readings with the reference differential;
• means for moving the lateral position of writing of the second track further from said first track when said difference is greater than said differential;
• means for moving the lateral position of writing of the second track toward said first track when said difference is less than said differential.