Existing operating system designs cannot guarantee isolation of user applications or system components from some system faults that occur in operating system services. If an error causes the failure by operating system services, the system can be corrupted or many system components which are dependent that services are affected. For constructing more reliable system, we have to manage this problem. In this paper, we propose the dependable system architecture by using microkernel concept. Because microkernel has reliable features such like isolation of system components, fault tolerance, modularity, small TCB, and so on, we can organize more dependable system architecture. Especially, separating state information, application and server can achieve more reliable system. To separate state information from process or server can help to recover system components.