The Research And Implementation Of Scientific Workflow System Based On GOS

In the recent years, grid computing has becoming a hot research of network computing, distributed computing and high performance computing. With the development of grid technology and the improvement of infrastructure, the requirements of grid application in grid agora are increasing. A lot of powerful and collaborative applications that need large resources are developed in grid environments. On the other way, the process of these applications growing more complex, they constrained with time, space and other resource, steps, procedures. In the present years, scientific workflow was invented as a new technology. It provides a new mechanism to execute complex process flow that composed of related sub tasks in grids. These sub tasks can execute automatically, thus improve the efficiency of grid environments.Scientific workflow appears with the development of grid computing. It can be defined as the composition of grid application which execute automatically on heterogeneous and distributed resources in a well-defined order to accomplish a specific goal. Scientific workflow system can not only definite, modify the execute process of applications in a flexible way, but also user the grid resource management system and schedule system. Tasks can be allocated in different grid nodes to optimize the grid usage. Scientists now emphasize on scientific workflow and use it in large grid project. The main contents of this paper are:This paper provides a scientific workflow system based on GOS on china national grid platform. The architecture can be divided into user portal layer, logical layer, and physical resource layer. The structure of the system established with low coupling and high scalable. The characteristic of the system is event driven mechanism and light weighted threading techniques. Large tasks can be executed automatically and handled concurrently. User support is also introduced, scientist can create workflows, manage tasks and monitor process timely according the graphical interface. All the lifecycle of the workflow will be inspected in hand.Scientific workflow system is implemented. We develop the components like parse engine, resource management, event service and fault tolerance, they can work mutually for parse tasks, execute workflows and communicate with each other. The structured workflow language is also designed, sequence, loops, conditional choice structure can be described with it.Applications executed with scientific workflow system in GOS gateway. Workflow system imported into GOS portal gateway, users can manage the workflow system like they use in GOS. At last, we execute MM5 mesoscale model with this system to test the functionality. The experiments shows that the system can create, execute, monitor the workflow efficiently and successfully.