nonsequential

Nonsequential is an adjective describing something that does not follow a sequence or linear order. The term is used across fields to indicate departures from a straightforward, stepwise progression.

In computing and data handling, nonsequential access refers to reading or writing data at non-adjacent addresses, often causing cache misses and variable throughput. It contrasts with sequential access, such as reading a contiguous file from beginning to end. Data structures may be nonsequential in memory layout, as with linked lists or trees, where elements are not stored contiguously. Systems optimize for nonsequential access using caching, prefetching, and technologies designed to improve locality.

In storage and performance contexts, nonsequential access is common in databases, file systems, and memory-intensive applications that work with scattered data. The drawbacks can be mitigated by larger caches, faster storage media, or data layout strategies that increase locality.

In narrative art and media, nonsequential storytelling refers to non-linear or non-chronological presentation of events. Flashbacks, parallel timelines, and multiple viewpoints are examples. This approach can reflect memory, cause-and-effect ambiguity, or thematic complexity.

The term also appears in scheduling or execution contexts to describe processes that do not strictly follow a prescribed order, including parallel or out-of-order execution in computing.

See also: sequential, nonlinearity, random access, memory locality.