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RK0: The Real-Time Kernel '0'

The Docbook provides design internals, rationale for design choices, some theory, and rich usage examples.

RK0 supports both paradigms. You can stick to one or use both, as demonstrated on the application example.

The Execution Image is a single-process. Roughly speaking, we enable concurrency within a single process by composing a thread of execution with a unique portion of the running stack. This composition gives us a schedulable unit, we chose to call a Task:
- User Tasks and System Tasks have the same privilege while running on separate stack pointers.
- Rationale for both decisions is in the Docbook.

Memory is mapped to the physical memory - we are talking about CPUs in the range of 8-256 KiB of RAM.
Application-specific needs for dynamic allocation and deallocation, as well as some kernel mechanisms, make use of an allocator that suits real-time demands: fixed-size blocks, word-aligned, O(1).

RK0 is a suitable system whose quality of service degrades quickly when not meeting time constraints. Tasks can't be unaware of each other and are actually cooperating concurrent units. The solution is domain-dependent. The hardware is domain-dependent. The deployed application was tested and is trusted. This is the typical closed model that most real-time critical applications fit.
It doesn't target any solution that until recently was handled by MMU-equipped, moderately powerful devices, running tailored full-fledged OSes (historically BSDs, until Linuxes prevailed); anything that faces it on the web, exposing to a high attack surface.

Q: Why is there no release yet?

A: A release is serious stuff. v1.0.0 will come when I can push:

a good Trace mechanism (it is ongoing)
can provide meaningful and honest system characterisation (it is ongoing)
the test harness in a way it works for any potential contributors (it works on my computer)