Computer data storage is a technology consisting of computer components
and recording media that are used to retain digital data. It is a core
function and fundamental component of computers.: 15–16
The central processing unit (CPU) of a computer is what manipulates data by
performing computations. In practice, almost all computers use a storage
hierarchy,: 468–473 which puts fast but expensive and small storage options
close to the CPU and slower but less expensive and larger options further
away. Generally, the fast technologies are referred to as "memory", while
slower persistent technologies are referred to as "storage".