Variability of black hole binary systems

X-ray light curves of black hole candidate systems reveal a variety of transient activity including quasi-periodic oscillations, dips, and bursts. These X-ray behaviors likely arise from nonsteady mass flow modulations in an accretion disk surrounding the compact object. The possible origin of the variabilities are discussed in terms of dynamical, viscous, and thermal instabilities in the accretion disk. The comparison of results from the global evolution of disks with X-ray observations can be used to provide constraints on proposed theoretical models, thereby, facilitating an understanding of the structure of the inner regions of accretion disks in these systems.