random access
1. A type of memory access in which storage locations can be accessed in any order. The term is applied primarily to the main memory of a processor where the access time to any word or byte is fixed, i.e. the access time to any item of information is independent of the address of that item and of the address of any previous item referred to. Main memory, in modern systems, is fabricated from semiconductor RAM or ROM, and the access time is typically of the order of 10–100 nanoseconds.

The term random-access memory has also been used to describe memory implemented on magnetic disk to distinguish it from serially accessed devices such as magnetic tape.

See also RAM disk.

2. A method of access to a file (especially a data file): a file is said to be randomly accessed if the sequence of transactions submitted to it does not match any sequence in which records may be organized.

ran·dom ac·cess Comput. • n. the process of transferring information to or from memory in which every memory location can be accessed directly rather than being accessed in a fixed sequence: [as adj.] random-access programming.