implement and compare the three page replacement algorithms.

- FIFO algorithm is provided for you as an example

- CLOCK algorithm is very similar to FIFO, but use a flag (used) to give a second chance to recently used pages

- Least Recently Used (LRU) algorithm requires a time stamp of pages used and picks the least recently used page to replace

- COUNT based algorithms uses requires a count of page access, least frequently used algorithm replace the page with the least count

// FIFO page Replacement algorithm

public static void pageReplAlgorithmFIFO(int vpage, Process prc)

{

int vPageReplaced; // Page to be replaced

int frame; // frame to receive new page

// Find page to be replaced

frame = prc.allocatedFrames[prc.framePtr]; // get next available frame

vPageReplaced = findvPage(prc.pageTable,frame); // find current page using it (i.e written to disk)

prc.pageTable[vPageReplaced].valid = false; // Old page is replaced.

prc.pageTable[vpage].frameNum = frame; // load page into the frame and update table

prc.pageTable[vpage].valid = true; // make the page valid

prc.framePtr = (prc.framePtr+1) % prc.allocatedFrames.length; // point to next frame in list

}

public static void pageReplAlgorithmCLOCK(int vpage, Process prc)

{

}

// LRU page Replacement algorithm

public static void pageReplAlgorithmLRU(int vpage, Process prc)

{

}

public static void pageReplAlgorithmCOUNT(int vpage, Process prc)

{

}