说明：  在PDP11 处理器上的麻省理工UNIX xv6操作系统源码的注解，帮助理解操作系统原理
(Xv6 is a teaching operating system developed in the summer of 2006 for MIT's operating systems course, 6.828: Operating System Engineering. We hope that xv6 will be useful in other courses too. This page collects resources to aid the use of xv6 in other courses, including a commentary on the source code itself.)