Inductance-saturation characteristics in thin film heads are measureme
nts of inductance as a function of write current. These measurements t
ypically exhibit a series of step-like inductance discontinuities as v
arious segments of the magnetic core saturate. In this work, we presen
t a framework for interpreting the location and magnitude of these dis
continuities and discuss what they reveal about the physical constitut
ion of the core.