Overwrite in tape recording is studied by three dimensional micromagne
tic simulation. We simulate thick tape media of randomly distributed e
llipsoidal particles with proper orientation distributions. Our initia
l calculations examine the overwriting of a low frequency NRZI signal
by a higher frequency signal. The simulation allows us to look at the
signal spectrum at each depth into the medium before and after overwri
te. We And that the residual low frequency signal is due to contributi
ons from all depths in the media. The effect of record equalization on
overwrite ratios is also studied.