Study On A Virtual Programmable Experiment Platform

Along with the long-distance education's rapid development, the studies about virtual experiment environment are accelerated, especially researches of virtual programmable experiment platform like computer interface technology. Because of the lag of the studies about virtual programmable experiment platform, today it can not fulfill the expectations of the increasingly long-distance education development. Based on the VPD model, under the support of national innovative fund project (01C26224210555), we deeply continue the research of virtual programmable experiment.The essentials of the programmable experiment are that the experiment programs control the programmable peripheral device using I/O instructions, so is the core of designing a virtual programmable experiment platform. We put forward a general VPEP (Virtual Programmable Experiment Platform) model, which consists of IDE and DVM (DOS Virtual Machine), virtual device drivers, virtual programmable devices and device drivers. In the VPEP model, the virtual device drivers intercept the I/O instructions when experiment's programs run under DOS VM, and communicate with virtual programmable devices through a synchronization message-switch mechanism based on synchronization event and sharable memory. So the two-direction real-time communication between DVM and virtual programmable device is realized. DVM can control virtual device, this almost satisfies the virtual programmable experiment. Through introducing interrupt message and virtual interrupt, the VPEP model solves the problem that the virtual programmable devices have not their interrupt resources, commendably suffices the requirements of virtual experiment with interrupt support.The VPEP model with synchronization message-switch mechanism resolves the problems of VPD: too many system resources occupation, non real-time communication and non-ideal experiment effect etc. The VPEP model has many excellences: good generality and Reliability, effortless and flexible interrupt experiment, vivid experiment etc, so the virtual programmable experiment is more satisfied. Finally, based on VPEP model, an elementary design scheme about virtual experiment tutor on the base of port status list aggregate change is present. The virtual experiment platform of interface technology is realized by the VPEP model. It proved that the VPEP model is general and reliable.