M6: Demand paging

In this milestone you need to implement paging of memory. This should build on the earlier milestone where you implemented a pager. The backing store for your paging system will be an NFS file called swap. You should implement a second-chance page-replacement algorithm.

Design issues

The MIPS does not feature hardware-maintained reference and dirty bits, which means you'll need to work out how to do this in software.

Most of the design in this section will come down to the appropriate choice of data structures. If you haven't already done so, you will need to work out your page table structure. Note that it should support a 64-bit virtual address space. You will also need to decide how to keep track of frames in your swap file. You may want to keep things simple at first be only concentrating on one process, however you should be aware that the next milestone will require you to handle multiple processes.

Assessment

To demonstrate that your code is indeed using the paging system you should artificially reduce the number of free frames, and run a program which uses a large heap.

You may want to write a command called thrash which writes data to a given number of pages and then reads it back (verifying that it has been read back correctly).