Data is written to a computer disk using a tiny electromagnet disk write head. We shall describe a coupled eddy current and micromagnetics model for a new design of the writer appropriate for perpendicular recording (it is hoped that this technique will allow greater data density on the disk, but significant design challenges remain). A simple finite difference formulation is used that allows us to verify that, before time discretization, the semi-discrete scheme obeys the same energy decay equality as the partial differential equation model. We show some numerical results for an s"academic" disk writer model.