题目：设计一个请求页式存储管理方案，并编写模拟程序实现

具体要求：

1、产生一个需要访问的指令地址流，为不失一般性，可以适当地（用人工指定地方法或用随机数产生器）生成这个序列，使得 50％的指令是顺序执行的。25％的指令均匀地散布在前地址部分，25％的地址是均匀地散布在后地址部分

2、　　页面淘汰算法采用 FIFO页面淘汰算法，并且在淘汰一页时，只将该页在页表中抹去。而不再判断它是否被改写过，也不将它写回到辅存

3、产生一个需要访问的指令地址流；指定合适的页面尺寸（例如以1K或2K为1页；指定内存页表的最大长度，并对页表进行初始化

4、每访问一个地址时，首先要计算该地址所在的页的页号，然后查页表，判断该页是否在主存。如果该页已在主存，则打印页表情况；如果该页不在主存且页表未满，则调入一页并打印页表情况；如果该页不在主存且页表已满，则按 FIFO页面淘汰算法淘汰一页后调入所需的页，打印页表情况 。逐个地址访问，直到所有地址访问完毕

-topics : design a request page memory management program, and the simulation program specific requirements : 1. have a need to visit the directive addresses flow, without loss of generality. be appropriate (to use artificial methods specified or random number generator) to form the sequence, makes 50% of the order was the order of implementation. 25% of orders evenly spread address some of the former and 25% of the addresses are evenly spread in the latter part two addresses. The algorithm uses pages out pages out of FIFO algorithm, and eliminate one, the only page in the page table to erase. No longer judge whether it be redrafted, it was not to return to the three auxiliary depositors, have a need to visit the directive addresses flow; designate the appropriate size of the page (for exam