Elements of the read path of a magneto-optic (MO) storage device are the lens that focuses the light onto the disk, the interaction with the disk, the propagation back through the objective lens, the polarization optics, and the detectors. This paper describes a program that simulates the effect of several disk parameters on the signal and noise of the read path. The program uses a scalar diffraction model and incorporates geometrical and optical properties of the disk, such as groove shape, signal pattern, and defects. An estimate of the signal current as a function of time is generated by the spot scanning along a length of the simulated disk that has an MO signal pattern and noise written on it. The signal calculated from the diffracted fields provides an estimate of the power spectrum, to which the effects of shot noise and amplifier noise are added to provide a total description of the read path.