  We address the question of the dependence of the fragility of glass forming
supercooled liquids on the softness of an interacting potential by performing
numerical simulation of a binary mixture of soft spheres with different power n
of the interparticle repulsive potential. We show that the temperature
dependence of the diffusion coefficients for various $n$ collapses onto a
universal curve, supporting the unexpected view that fragility is not related
to the hard core repulsion. We also find that the configurational entropy
correlates with the slowing down of the dynamics for all studied n.
