Cache

Caching is a partial solution for bottlenecks. A cache temporarily stores frequently used data on faster storage for easy access.
For example, a web browser will cache a web page on the hard drive, because accessing data from the drive is faster than going to the internet to get the webpage again!
Likewise, the CPU will temporarily cache data in special fast memory (called L1, L2, and L3 Cache) to circumvent the bottleneck involved in fetching data from RAM.
Computer Science students spend considerable time thinking about the implications of different caching strategies!
For you, it is just important to have a general impression of what caching means so you'll understand topics like:
- The features of a CPU you might choose
- Why you can still view a cached web page when you are no longer connected to the internet.

Analogy: Borrowing Books

Imagine you borrow books from the library and friends, but you can keep only four at a time.
● When you need to trade current books for something else, how should you decide which ones to return?
● There are two standard approaches:
- Cost Optimization: Return the books that are easiest to retrieve if you need them again.
- LRU: Least Recently Used Optimization: Return the ones you have not used in the longest time.

Watch this 4-minute video on caching.

Hardware 1 (10)