What is a cache?
A cache -- pronounced CASH -- is hardware or software that is used to store something, usually data, temporarily in a computing environment. A small amount of faster, more expensive memory is used to improve the performance of recently accessed or frequently accessed data that is stored temporarily in a rapidly accessible storage media that's local to the cache client and separate from bulk storage. Cache is frequently used by cache clients, such as the CPU, applications, web browsers or operating systems (OSes). Cache is used because bulk, or main, storage can't keep up with the demands of the cache clients. Cache shortens data access times, reduces latency and improves input/output ( I/O ). Because almost all application workloads depend on I/O operations, caching improves application performance. How cache works When a cache client needs to access data, it first checks the cache. When the requested data is found in a cache, it's called a cache hit. The percent of attempt...