Task scheduling and calculating reliability in tree-structured grid services using colored petri net

Grid computing is a new emerging technology aiming at large-scale resource sharing, and global-area collaboration. In Grid environments, the resource management system RMS is responsible for the scheduling and execution of tasks. The RMS divides the incoming tasks into several subtasks and distributes them among grid resources for parallel execution. Then, the RMS integrates the received results into the entire task output, which is requested by the user.in this paper tree structured of grid services is considered which within RMS and resources several links were found. Reliability in grid services is defined as a probability that the correct output is produced in time less than a certain time. Reliability problem is one of important measures in quality of services (QoS). For modeling subtasks and reliability evaluation in this paper is used colored petri nets and CPN tools version4. To demonstrate the accuracy of proposed model a virtual tree structured grid service with four resources is used and results is shown in output text file.