  The chiral surface electrons in the bulk quantum Hall effect probably form
the first extended system in which conductance fluctuations can be calculated
non-perturbatively in the presence of disorder. By use of the Kubo formula with
appropriate boundary conditions, we calculate exactly the variance of
conductance with non-perturbative methods. We find that the conductance
fluctuations of this system are ``nonuniversal'' and the variance of the
conductance scales in a very peculiar way. This result can be checked with
exact computation using the Landauer-Buttiker formula and both methods show the
same scaling behavior. We have also calculated the diffusion constant
fluctuations exactly. We find that the diffusion constant fluctuations vanish
and thus play no role in the conductance fluctuations.
