The development of software for Electric Load Management Center (ELMC) is presented in this paper. Based on the embedded real-time operating system VxWorks, ELMC performs multiple tasks including periodic and aperiodic ones. While rate monotonic (RM) algorithm is still used to process periodic tasks, we propose a condition triggered algorithm (CTA) to schedule aperiodic tasks by using VxWorks's semaphore mechanism. The schedulability test is also presented in this paper. We improved the test conditions to meet the needs of this system. At last, several tests are held and the results proved that compared with other scheduling procedures, the hybrid scheduling scheme has greatly improved the real-time capability and shortened response time for urgent tasks.
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