ADOK: a minimal object oriented real-time operating system in C++

Most embedded software is currently developed using the C programming language, even though its low level of abstraction requires a lot of effort to the programmer. The C++ language is a better choice because: it raises the level of abstraction; it is strongly typed, so it prevents many common programming mistakes; it can be made as efficient as C through fine-grained customisation of memory mechanisms; it can be easily adapted to domain-specific needs. In addition, recent compilers have grown in maturity and performance, and the new standard considerably improves the language by introducing new concepts and an easier syntax. In this paper we present ADOK, a minimal Real-Time Operating System entirely written in C++ with the exception of a few lines of assembler code. It directly offers a C++ interface to the developer, and it provides a flexible scheduling framework which allows the developer to customise the scheduling to its needs. In particular, we implement a two-level scheduler based on Earliest Deadline First, the Stack Resource Policy protocol for sharing resources and support for mode changes. We demonstrate through examples and a small case-study that ADOK can substantially improve productivity without sacrificing on performance.