Chapter 3. Cache Migration Patterns

	"To improve is to change; to be perfect is to change often"
	--Winston Churchill

The concept of caching goes back to the very early days of computer architecture. Caching is the process of storing data in an easily accessible store so that requests for the cached data can be fulfilled faster. The Merriam-Webster dictionary defines cache in two ways. In the literal sense, it is defined as:

"A group of things that have been hidden in a secret place because they are illegal or have been stolen."

In the computing sense, it is defined as "a part of a computer's memory where information is kept so that the computer can find it very quickly." Cache is used in both hardware and software. In this chapter, unless otherwise specifically mentioned, all the references to cache refer to cache used in software applications.

In software applications, cache is extensively used to speed up data access. The use of...