DEVS is a formalism to describe generic dynamic systems in a hierarchical and modular way. We present new techniques for executing DEVS and Cell- DEVS models in parallel and distributed environments based on the warped kernel. The parallel simulator PCD++ has been extended to support optimistic simulations. A non-hierarchical approach is employed to reduce the communication overhead. A two-level user-controlled state-saving mechanism is proposed to achieve efficient and flexible state saving at runtime. It is shown that optimistic PCD++ markedly outperforms other alternatives, and considerable speedups can be achieved in parallel and distributed simulations.