Storage
Storage
Computer data storage, computer memory, and often casually storage or memory refer to computer components, devices and recording media that retain digital data used for computing for some interval of time. Computer data storage provides one of the core functions of the modern computer, that of information retention. It is one of the fundamental components of all modern computers, and coupled with a central processing unit (CPU, a processor), implements the basic computer model used since the 1940s.
Storage in popular usage differs from primary storage in that it is not directly accessible by the CPU. The computer usually uses its input/output channels to access secondary storage and transfers desired data using intermediate area in primary storage. Storage does not loose the data when device is powered down—it is non-volatile. Consequently, modern computer systems typically have an order of magnitude more secondary storage than primary storage and data is kept for a longer time there. Tertiary storage or tertiary memory,[2] is a system where a robotic arm will mount (insert) and dismount removable mass storage media into a storage device according to the system's demands. It is primarily used for archival of rarely accessed information, since it is much slower than secondary storage (e.g. 5-60 seconds vs. 1-10 milliseconds). This is primarily useful for extraordinarily large data stores, accessed without human operators. Typical examples include tape libraries and optical jukeboxes.
