Dual OS Support Peripheral Device Encapsulation

The need of extensive computing capacity is expanding all the time. Especially in company providing network service, adding servers physically requires much more cost. Also in embedded system, resource is also very limited. That is why virtulization is so popular in research and industry application. A lot of virtulization technique is raised to supply great computing capacity with multiple operating system running synchronously in a single real machine. Of all the aspects affecting real time performance of a computer, I/O processing has played a major role. Because I/O bound process has to wait for device to be free and thus increase response time which may delay them go beyond deadline. The system-on-a-chip technology provides the scratch-pad memory(SPM), which is small, isolated and located on chip. We implement a little operating system running in SPM (SPMOS). The SPMOS provide virtual I/O interface for general operating system. Different I/O requestis buffered and scheduled if necessary. Also, with proper memory checking mechanism, we could prevent malicious attacks on SPM, which means that any program running in the SPM could be protected effectively. Experiment shows that the SPMOS based virtual I/O interface is efficient and practical.