2.设计一个虚拟存储区和内存工作区，并使用下述算法计算访问命中率。

1) 最佳置换算法（Optimal）

2) 先进先出法（Fisrt In First Out）

3) 最近最久未使用（Least Recently Used）

4) 最不经常使用法（Least Frequently Used）

5) 最近未使用法（No Used Recently）

其中，命中率＝１－页面失效次数／页地址流长度。

试对上述算法的性能加以较各：页面个数和命中率间的关系；同样情况下的命中率比较。

-2. To design a virtual memory storage area and work area, and access using the following algorithm to calculate the hit rate. 1) The best replacement algorithm (Optimal) 2) FIFO (Fisrt In First Out) 3) most recently from lack of use (Least Recently Used) 4) the least frequently used method (Least Frequently Used) 5) does not use a recently (No Used Recently) where hit rate = 1- invalid page number/page address stream length. Test the performance of the algorithms to be compared with each: the page number and the relationship between hit rate　the same hit rate in case of comparison.