  The restricted solid-on-solid (RSOS) model is a model of continuous-time
surface growth characterized by the constraint that adjacent height differences
are bounded by a fixed constant. Though the model is conjectured to belong to
the KPZ universality class, mathematical progress on the model is very sparse.
We study basic properties of the model and establish bounds on surface height
fluctuations as a function of time. A linear fluctuation bound is proven for
all dimensions, and a logarithmic fluctuation lower bound is given for
dimension one. The proofs rely on a new characterization of RSOS as a type of
first passage percolation on a disordered lattice, which is of independent
interest. The logarithmic lower bound is established by showing equality in
distribution to the minimum of a certain dual RSOS process.
