Chapter 8  * Main Memory  315 

  --> not so much this semester: Swapping  8.2 p 322   Backing Store  p 322  

 Continguous Memory allocation  8.3 324  
_ Table of Memory/ List of holes 
_ Dynamic Storage allocation Problem 
  first fit  p326  
   best fit  p327  
  worst fit  p327  
_ External Fragmentation  p327  
_ Internal Fragmentation  p327  
_ 50*percent rule  p327  
_ Compaction  p327  

 Paging  8.4 328  
_ vocab: pages, frames, logical memory, physical memory 
_ understand issues involving: 
   -size 
   -shared pages  p 336  
   -OS view vs user view  // logical programming view vs OS view of pages/frames/page table
   -hardware support *p332  (page table, TLA)
 
 Chapter 9 * Virtual Memory  315  

 Demand Paging  9.2 322  
_ pure demand paging  p364  
_ locality of reference  p364  
_ "fast" fork * copy*on*write  9.3 p367  
-  Page Replacement  9.4 p369  
_ over*allocated memory  better CPU utilization and throughput  

- Options on page*fault  with no free frames  
_ terminate process * but which/why/how? 
_ swap out process and frames 
_ replace single page -- let's do this!


---> below this line, not covered this semester in detail- not on in any direct fashion

- I/O memory requirements compete or fixed in OS?   395 – 9.7.3 memory mapped 
I/O  
- page*fault service  without dirty bit    363   
_ Find page on disk 
_ Find free frame 
  use it if found 
  if not select a victim 
  write victim to disk  update tables  
_ read page into free frame  update tables  
_ restart  wake*up  user process 
- Use dirty bits to avoid some writes  p371  
- small gains in demand paging give great gains 
- Page replacement algorithms  369  
- FIFO  p373 , optimal  p374 , LRU  p376 , LFU/MFU  p380  _ Belady’s anomaly  p374  
- Thrashing  9.6 p386