With the rapid development of the computer network, distributed applicationsbecome main stream gradually. Because of its inherent shortcomings, traditionalcentralized server system limits the development of network service to multi-aspectmore and more, people also turn to use distributed server system slowly. Usingdistributed system has many advantages, such as sharing resource、improving systemreliability and reducing business cost. In order to meet the need of distributed andparallel server system, which h...