IBM®
Skip to main content
    United States [change]    Terms of use
 
 
 
    Home    Products    Services & solutions    Support & downloads    My account    
IBM Research

High Fidelity Track Following

A modified servo decode circuit was implemented in a field programmable gate array and used to derive the position error signal (PES) for closed loop trackfollowing. A plot of the track-following error with a maximum error of 0.35 μm (except for three single sample mis-decodes) is shown below. Assuming statistically independent write and read track-following processes, we estimate the total tracking misregistration to be √2 × 0.35 or 0.5 μm. Given that the readback process requires a reader width of 0.5 μm, this magnitude of the position error signal would permit a written trackwidth of 1.5 μm. Other factors such as the width of the edge erase band, the uniformity of the written signal, the offtrack reading behavior, and head tolerances also affect the written trackwidth. However write gap reduction and pole trimming are means for controlling written uniformity and, to some extent, the size of the erase band. The fidelity of trackfollowing on flexible media as shown here poses a stronger limit on written trackwidth.

track-following error plot

Click here to view a movie on tape dynamics.






  

Click for more information

Link to Advancing Tape Areal Density

Advancing Tape Areal Density

Link to GMR Heads on Tape

GMR Heads on Tape

Link to Write/Read

Writing and Reading 1.5 Micron Tracks


    About IBMPrivacyContact