1. Field of the Invention
The present invention relates generally to recording on magnetic tape, and more specifically to correct placement of written tracks on magnetic media relative to the read elements.
2. Background of the Invention
Advanced tape storage devices read and write data on multiple data tracks, which run parallel to each other over the length of the tape. However, there is an inherent problem associated with independent data tracks. As the tape moves past the tape head, lateral drift of the tape can result in the head reading or writing on the wrong data track. This would obviously degrade the quality of data storage and retrieval. To ensure that the tape heads are accurately positioned relative to the tape, dedicated servo tracks are usually recorded on the tape parallel to the data tracks. These servo tracks are read by servo readers on the tape head. The servo readers then signal mechanisms within the tape drive that are capable of adjusting the tape head in order to maintain proper alignment with the data tracks.
As higher track densities are achieved in tape drives, the need to place the written tracks in precisely the correct locations becomes crucial. As explained above, a track-following servo system is typically employed in this effort. Unfortunately, the servo readers are laterally displaced along the direction of tape motion from the data writers. This leads to errors in placing the written track in the correct location. These errors can arise from non-ideal head construction (bump alignment) and non-perpendicular tape motion with respect to the head (azimuth error).
Therefore, it would be desirable to have a method for aligning write tracks on magnetic tapes in order to compensate for non-ideal head construction and non-ideal motion of the tape past the head.