Least Recently Used (LRU)
Basic idea: we can’t look into the future, but let’s look at past experience to make a good guess.
LRU: on replacement, remove the page that has not been used for the longest time in the past.
Implementation: to really implement this, we would need to time stamp every reference, or maintain a stack that’s updated on every reference. This would be too costly.
So, we can’t implement this exactly, but we can try to approximate it.
- why is an approximate solution totally acceptable?