里面包含了众多的编写操作系统的底层软件，好难找啊，大家要珍惜啊！包括ls,nasm，djgpp，等等等等。是个集合包-of which contains a large number of the operating system to prepare the bottom of software, the difficulty in finding good ah, we must cherish ah! Including ls, NASM, DJGPP, so on and so fort