RTOS NOTES Hard realtime OS has less jitter and Soft real time jitter has High jitter jitter : it is the time between two interrupt Event driven systems switch between tasks based on their priorities while time sharing systems switch the task based on clock interrupts. Most RTOS’s use a pre-emptive scheduling algorithm. The most common designs are Event-driven – switches tasks only when an event of higher priority needs servicing; called preemptive priority , or priority scheduling. Time-sharing – switches tasks on a regular clocked interrupt, and on events; called round robin . A task has three stages 1. Runing 2.Ready 3.Blocked(Waiting for an event,I/O for example) On simpler non-preemptive but still multitasking systems, a task has to give up its time on the CPU to other tasks, which can cause the ready queue to have a greater number of overall tasks in the ready to be executed state ( resource starvation ). laxity = Absolute deadline...
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