Computer simulations of dynamical systems are spatial discretizations in wh
ich the finite machine arithmetic space replaces the continuum state space
of the original system. Any trajectory of a spatial discretization of a dyn
amical system is thus eventually periodic, so the dynamical behaviour of su
ch computations are essentially determined by the cycles of the discretized
map. Such dynamical behaviour depends seemingly randomly on the fineness o
f the discretization mesh. In this paper statistical properties of the maxi
mal cycles of spatial discretizations are investigated for some systems suc
h as the tent map, rotations on a circle and toral endomorphisms.