A multitasking operating system permits application programs (and their developers) to influence a schedule of execution of program threads which constitute the application programs by specifying parameters for the program threads. The parameters indicate each thread's priority level and dispatch class...http://www.google.com.tw/patents/US5247675?utm_source=gb-gplus-share專利 US5247675 - Preemptive and non-preemptive scheduling and execution of program threads in a multitasking operating system
