rkernel

rkernel is a term used in computing to describe a modular, real-time oriented kernel designed for embedded and time-sensitive applications. It emphasizes determinism, a minimal codebase, and isolated components to reduce latency and improve reliability.

Architecturally, rkernel often follows a microkernel-like approach with a small core that provides inter-process communication (IPC), scheduling, and resource management, while drivers and services run as user-space tasks or loadable modules. Real-time scheduling policies such as fixed-priority preemption or earliest-deadline-first (EDF) may be supported, along with mechanisms for interrupt handling, memory protection, and deterministic timers. The kernel might expose either POSIX-compatible interfaces or tailored RTOS APIs for application development.

Implementation and use: rkernel implementations are typically written in C or C++, with some projects exploring memory-safe languages like Rust. They are targeted at resource-constrained hardware (microcontrollers and system-on-chips) as well as larger embedded systems requiring strict timing guarantees. Typical applications include robotics, automotive control, industrial automation, and critical data processing where predictable latency is essential.

History and community: The term rkernel has been used by multiple independent projects rather than referring to a single standard. As a result, features, APIs, and maturity vary across implementations, and compatibility is not uniform. Documentation ranges from concise to comprehensive depending on the project.

See also: real-time kernel, microkernel, real-time operating system, deterministic scheduling, embedded systems.