Hierarchy

Caching

Speed up access by using faster storage as a cache for slower storage.

Faster storage holds a subset of the data from the slower storage. Exploits principle of locality where recently accessed data is likely to be accessed in the near future.

CPU Cache

CPU cache is fast memory between CPU and RAM. Holds recently used data or instructions to save memory accesses.

Caching Disk Access

Keep a subset of disk data in main memory. Minimises access to hard disk, greatly improving performance

Caching Internet Access

Keep a subset of the internet’s data on disk. Minimises network access, greatly improving performance.