nonmonolithic

Nonmonolithic is an adjective used to describe architectures or systems that are not built as a single, inseparable unit. In computing, nonmonolithic often refers to kernel or operating system designs in which functionality is distributed across multiple components, processes, or address spaces rather than contained in one monolithic block.

A nonmonolithic kernel is designed to minimize the portion of code running with high-privilege kernel rights and to rely on isolation and interprocess communication to implement services. Microkernel architectures such as Mach and L4 are emblematic, providing a minimal kernel with most services implemented as user-space processes; exokernel designs push the boundary further by exposing more hardware resources to applications. Many contemporary systems also use modular or loadable kernel components, which some describe as nonmonolithic in practice because functionality can be added or updated without rebuilding a monolithic kernel.

Beyond kernels, nonmonolithic describes software architectures that avoid a single codebase or deployment unit, including microservices and service-oriented architectures, where independent components communicate through defined interfaces.

Advantages include fault isolation, easier maintenance, and scalable upgrades; disadvantages often involve IPC or network overhead, increased complexity, and operational challenges.

In practice, many systems blend nonmonolithic concepts with performance optimizations, and the term is used flexibly across domains. See also monolithic kernel, microkernel, modular kernel, Linux, Windows NT, MINIX, Mach, L4, microservices.