  We describe software that simulates the hardware of a scanning force
microscope. The essential feature of the software is its real-time response,
which is critical for mimicking the behavior of real scanning probe hardware.
The simulator runs on an open-source real time Linux kernel, and can be used to
test scanning probe microscope control software as well as theoretical models
of different types of scanning probe microscopes. We describe the
implementation of a tuning-fork based atomic force microscope and a dc
electrostatic force microscope, and present representative images obtained from
these models.
