  The large N limit of extremal non-supersymmetric Type-I five-dimensional
string black holes is studied from the point of view of D-branes.
  We find that the agreement between the D-brane and the black-hole picture is
due to an asymptotic restoration of supersymmetry in the large $N$ limit in
which both pictures are compared.
  In that limit Type-I string perturbation theory is effectively embedded into
a Type-IIB perturbation theory with unbroken supersymmetric charges whose
presence guarantees the non-renormalization of mass and entropy as the
effective couplings are increased. In this vein, we also study the near-horizon
geometry of the Type-I black hole using D5-brane probes to find that the low
energy effective action for the probe is identical to the corresponding one in
the auxiliary Type-IIB theory in the large N limit.
