说明：  UCOS一种只支持优先级抢占型调度的操作系统。它不支持同一个优先级有2个及以上的任务同时运作。 本文修改的UCOS支持不同优先级调度的同时，支持同一个优先级有2个以上的任务以时间片轮转方式进行调度。 这个就是UCOS和修改的UCOS的区别。
(UCOS only support a priority-based scheduling of the operating system to seize. It does not support the same priority level 2 and above have the task of operating at the same time. This article uCOS modified to support different priority scheduling at the same time, support the same priority level has two more tasks to the time slice approach to scheduling rotation. This is uCOS uCOS and modified difference.)