We show that the numerical method based on the off-equilibrium fluctuation-
dissipation relation does work and is very useful and powerful in the study
of disordered systems which show a very slow dynamics. We have verified th
at it gives the right information in the known cases (diluted ferromagnets
and random field Ising model far from the critical point) and we used it to
obtain more convincing results on the frozen phase of four-dimensional spi
n glasses. Moreover we used it to study the Griffiths phase of the diluted
and the random field Ising models.