说明：  xada为用ada语言开发的操作系统 ada语言是美国国防部指定的军用语言，用它开发操作系统有独到之处。这个操作系统实现了最简单的中断，端口读写等功能，比较初级，适合初学者，必须在linux环境，gcc版本3.2.x下编译，gcc的高版本下编译有问题
(xada ada language used for the development of the operating system ada language of the United States Department of Defense designated the military language , and it is unique in the development of the operating system. This operating system to achieve the most simple interrupted, port functions such as reading and writing, compared primary, for beginners, in linux environment, gcc version 3.2. x under compiler, gcc version under the high compiler problems)