高可信赖实时操作系统的防危调度机制

为增强实时操作系统的防危性，在分析现有调度机制的基础上，探讨了最大关键度优先的调度算法，该算法是一种混合型的优先级实时调度算法，由静态优先级、动态子优先级和静态子优先级3部分组成，综合了固定优先级调度算法和动态优先级调度算法的优点，既可充分利用处理器资源，又能在发生瞬时过载时保证关键任务不受非关键任务的影响，从而增强了实时操作系统的防危性。

To buildup the safety of real time operating system, after status quo of existing scheduling mechanism analyzed, brought forward a kind of novel safety scheduling mechanism based on Maximum Criticality First (MCF). MCF is a hybrid priorities real time scheduling algorithm which consisting of three parts, the first two parts are the assignment of the importance and user priority, which is done statically, the second part is the assignment of the dynamic priority based on minimum laxity first scheduling algorithm. MCF synthesizes the strongpoint of the fixed priority scheduling algorithm and the dynamic priority scheduling algorithm. By this way, MCF not only takes full advantage of resources such as CPU, also make critical task not suffer from other non critical tasks at transient overload. The safety of real time operating system is improved with MCF.