by Dinesh Thakur

Auxiliary memory is the lowest-cost, highest-capacity, and slowest-access storage in a computer system. It is where programs and data are kept for long-term storage or when not in immediate use. Such memories tend to occur in two types-sequential access (data must be accessed in a linear sequence) and direct access (data may be accessed in any sequence). The most common sequential storage device is the magnetic tape, whereas direct-access devices include rotating drums, disks, CD-ROMs and DVD-ROMs.