The Research And Design Of FPGA Remote Experiments Services Based On WSRF

Distance education has been developed considerably with the popularization of Internet and the appearance of multimedia technology, virtual instrument technology and computer simulation technology. There has a sharp increase in the number of college students. The laboratory equipments are expensive and laboratory resources can not meet current needs. In the face of these problems, the establishment of the remote experiment can make good use of limited resources to meet the needs of experimental teaching. The issue stems from the study of new models for the computer hardware experiment under the school network environment.This paper bases on WSRF (Web Service Resource Framework) of the FPGA (Field Programmable Gate Array). The described and implemented remote experiment service is one aim for the course about remote experiment of computer hardware which is based on FPGA opened by colleges and universities. Above all the analysis of Web services specifications and technology advantages in resources was done, technology specifications about how to fulfill interoperability was systematic outlined, in which this paper focus on research of how to keep state and the service package model in the WSRF service. The definition of the state of resource properties and the feature of automatic update was studied. Combined with FPGA hardware experimental process which contains design, configuration and authentication, and the WSRF protocol which contact Web service and state resources by implicit resource model, and based on the thought of service-oriented architecture, four level structures which is based on WSRF of FPGA was presented.On the implementation, the client side was designed and realized deftly and practically to enhance the efficiency of the remote experiment customers experience. The problem of reading files under the mode of B/S was resolved with the skill of the mutual assorted call of the JS and Flex. The students were enabled to interactively experiment well by making good use of the rich interface elements and data model of the Flex itself. The experimental results were presented humanisticly, intuitively and iconically. This greatly enhanced the users' experience and improved the student's interest in experiment.With regard to the server, this paper firstly introduced the process of how to pack experimental service with service resource model and its advantages. Then, the experimental service based on WSRF was fulfilled with WSRF.NET, namely ALU experimental service. This paper packed service according to WSRF specifications, and adopted standard web service description language (WSDL) to describe the service interfaces, entry parameters and returned result type of service. To make use of the definition of WSRF resource properties and endpoint references, the problem of how to keep state during experiment was resolved. For the resource scheduling in the server, this paper compared current scheduling algorithm, such as first come first serve, priority first serve, small service first serve, and then feedback mechanism was presented which made use of service time of history to predict execution time of current service, and firstly serve the service with the fastest completion time, which could improve the utilization of the machine.After the designing of the client side and the service side, this paper debuged them jointly .The prototype system runs completely normal and achieves the expected goals.