DUAL SYSTEM, DUAL-SWITCHING METHOD THEREOF, AND COMPUTER RECORDING MEDIUM FOR STORING PROGRAM TO PERFORM THE SAME

摘要

PURPOSE: A dual system, a dual-switching method thereof, and a computer-recording medium for storing a program to perform the same are provided to perform simply a dual-switching function by using a semaphore and a daemon process. CONSTITUTION: An active device and a standby device generate a semaphore and a daemon process if a dual system is operated(201-203). The active device and the standby device maintain constantly a dual switching point by using the semaphore and the daemon process when the active device generates a dual command(204-205). Each daemon process of the active device and the standby device performs a dual switching function at the dual switching point(207-208). The standby device finishes the dual switching process by performing a process prior to the dual switching process.