处理事件请求(processing time requirement), 包括任何操作系统延时(OS delay)是以数十分之一秒(tenths of seconds)或者跟短.
RTOS的一个关键的特性是一致性的等级(level of its consistency), 关于他花费的时间来接受和完成一个应用任务. 衡量这个变化的叫做抖动(jitter).
一个硬RTOS比一个软RTOS有更少的抖动(jitter).
主要的设计目标不是高吞吐量(throughput), 而是一个软或硬性能分类的保证.
An RTOS that can usually or generally meet a deadline is a soft real-time OS, but if it can meet a deadline deterministically it is a hard real-time OS.
一个RTOS有用一个关于调度(scheduling)的高级算法.
Scheduler flexibility enables a wider, computer-system orchestration of process priorities, but a real-time OS is more frequently dedicated to a narrow set of applications.