Helpful hints

• Implement your backing store as an OpenFile with the name ``Swapfile.pid'' where pid is the id of the process that owns the file. This will help in debugging. Create this file as part of the AddrSpace constructor.

• Implement your inverted page table as a hash table for quick indexing. Remember to make the size of the inverted page table a prime number.

• Pick a simple page replacement algorithm to test your implementation. When you are sure it works, implement an efficient page replacement algorithm.

• Swap a page to the disk only if its modify bit is set.

• Invalidate all TLB entries on a context switch.

• Read Section 6.4 in Thomas Narten's handout.

• If you are unclear about how to compile and run test programs for Nachos, see the handout for Lab 3.

When you finish making changes to the file, compile in the usual way - type gmake depend and then gmake nachos to create a new executable. Note that the -x option provided by Nachos runs a user program on top of Nachos.