Patent ID: 8154811

Claim:
A method of electronically measuring reader/writer offsets in a tape drive head, said method comprising: writing a plurality of sequentially adjacent data tracks on a tape with a write head; measuring error rate information while reading a data track of said plurality of sequentially adjacent data tracks with a read head of a tape drive, wherein said data track comprises an interior data track of said plurality of sequentially adjacent data tracks which is surrounded by other data tracks of said plurality of sequentially adjacent data tracks; building a bathtub shaped curve from a set of said error rate information accumulated by reading said data track at a plurality of offsets of said read head relative to said data track; and measuring offset of said read head relative to said write head by determining an offset of said read head which correlates to a magnetic center of said data track as represented by a center point between edges of said bathtub shaped curve, wherein said measuring error rate information while reading a data track of said plurality of sequentially adjacent data tracks with a read head of a tape drive further comprises: capturing serial variables including a top position error signal value and a bottom position error signal value for each offset position while performing said reading.