CIS 656

On Wednesday 09/26.09 hand in 

Comer p 76 problem 4.1.

Comer p 87 problem 5.3.
This is a discussion of the ``remove the least recently used'' policy: The 
Cache has space for at most N entries. Every time an (IP adress -> Phys 
adress) map (or binding) is adverised, one of two things happens:
If the map is already in the cache, it gets a new timestamp. 
If the map is not yet in the cache, it is put in the cache with the new 
time stamp. In that case, if the cache already was full, first the entry 
with the oldest timerstamp is removed.  
Usually this ``least recently used'' policy is quite good. In what 
special situation is it bad?
What do we mean by ``good'' or ``bad''? 

Comer p 87 problem 5.9.