  We simulate via a Discrete Element Method the tapping of a narrow column of
disk under gravity. For frictionless disks, this system has a simple analytic
expression for the density of states in the Edwards volume ensemble. We compare
the predictions of the ensemble at constant compactivity against the results
for the steady states obtained in the simulations. We show that the steady
states cannot be properly described since the microstates sampled are not in
correspondence with the predicted distributions, suggesting that the postulates
of flat measure and ergodicity are, either or both, invalid for this simple
realization of a static granular system. However, we show that certain
qualitative features of the volume fluctuations difficult to predict from
simple arguments are captured by the theory.
