1. Nachos Project 3

2. Goal Make Nachos can run following test cases in the same time
/test/matmult.c
/test/sort.c
The problem is that both of the test cases require a lot of memory(larger then physical memory)

3. Create Disk swap = new SynchDisk Use the disk as the swap space
Access the disk by
kernel->swap->WriteSector
kernel->swap->ReadSector
See “synchdisk.cc” and other files in /filesys

4. Maintain Three Tables Physical memory FrameTable 1 2 3 4 PageTable 1 2
SwapTable 1 2 3 4

5. PageTable For each entry in PageTable
unsigned int virtualPage; //virtual memory page
unsigned int physicalPage; //if in physical memory
bool valid; //if in physical memory
bool use; //been used(read or write)
bool dirty; //been modified

6. FrameTable For each entry in FrameTable Bool valid; //if being used
Bool lock;
AddrSpace *addrSpace; //which process is using this page
Unsigned int vpn; //which virtual page of the process is stored in this page

7. SwapTable For each entry in SwapTable Bool valid; //if being used
Bool lock;
AddrSpace *addrSpace; //which process is using this page
Unsigned int vpn; //which virtual page of the process is stored in this page
(same as the FrameTable)

8. Address Mapping
Physical Address = pageTable[(virtual address / PageSize)].physicalPage * PageSize + (virtual address % PageSize)

9. Addrspace::Load Load 1 page a time
Ask for 1 page, if the FrameTable is full, select 1 frame and put it into SwapTable
Mapping Address

10. Create new class “Memory Manager”
Int TransAddr(AddrSpace *space, int virtAddr); //return phyAddr
Bool AcquirePage(AddrSpace *space, int vpn); //ask a page for vpn
Bool ReleasePage(AddrSpace *space, int vpn); //free the page
Void PageFaultHandler();
//will be called when manager want to swap a page from SwapTable to FrameTable and the FrameTable is full

11. Hand in report Report Mail your code and report to yyergg@gmail.com
tar zcvf b99xxxxxx.tar.gz ./nachos-4.0
Report
Why the result is not congruent with expected
How you modified Nachos to make it support multiprogramming – important code segments
Mail your code and report to
Deadline Jan