说明：  Operating System.从事嵌入式的人至少须掌握一个嵌入式操作系统(当然掌握两个更好),这在嵌入式的所有技术中是最为关键的了。目前最重要的RTOS主要包括：
(Operating System. Embedded in the people required to master at least one embedded operating system EC (2 better grasp of course), all in Embedded technology is the most critical. The most important RTOS include :)