说明：  rtems全称real time milltary os,是美国军方原使用的操作系统。这里是最新代码。rtems的特点是架构先进，当然代码比较难懂。
(The the rtems full name of the real time milltary os, operating system originally used by the U.S. military. Here is the latest code. The rtems the advanced architecture, of course, the code difficult to understand.)