模拟内存换页算法，包括FIFO（先进先出first in first out）,OPT(动态分配optimal),LRU(最近不使用latest use recently),LFR(最近最低频率lowest frequency recently),NUR(最近不使用no used recently）-Analog memory paging algorithms, including FIFO (first in first out first in first out), OPT (dynamic allocation optimal), LRU (recently does not use latest use recently), LFR (the lowest frequency of the recent lowest frequency recently), NUR (do not use the recent no used recently)