说明：  Nachos的全称是“Not Another Completely Heuristic Operating System”，它是一个可修改和跟踪的操作系统教学软件。它给出了一个支持多线程和虚拟存储的操作系统骨架，可让学生在较短的时间内对操作系统中的基本原理和核心算法有一个全面和完整的了解。
(Nachos full name is " Not Another Completely Heuristic Operating System" , it is a modifiable and track the teaching of the operating system software. It gives the skeleton to support multi-threading and virtual storage operating system, allows the students in a short period of time on the operating system, the basic principles and core algorithm has a full and complete understanding.)