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How to build a hybrid solar/wind energy harvester?

Vector, list and tree

Choice of containers Information technology, even embedded devices, is about information gathering, processing or calculation, and control. Input and data needs to be juggled around and maybe sorted. In this article, we want to point out some fundamental implications in the choice of a data container. Vector The first container is the array or “vector”. […]


Priority inversion

I found the inspiration for this article while working on a consultancy job: Priority inversion. In computer science, priority inversion is a (potential) problematic scenario in scheduling in which a high priority task is indirectly preempted by a medium priority task effectively inverting the relative priorities of the two tasks. ( To put it more […]


Real-time: designing task algorithms

In an earlier article, we talked about real-time behaviour, meeting deadlines and how a real-time OS operates. To recapitulate: the highest priority task that becomes runnable pre-empts all other tasks and runs to completion (until it ends, yields or sleeps). Also, we can have different layers of processing. high-to-low priority run-to-completion interrupts run first (all […]


Real-time scheduling: no locks, please.

In a previous post, the assignment of priorities was discussed. There are a couple of axioms involved. One must mention at least these two: No resource sharing, locks or busy-waits. Static priorities (i.e. the task with the highest static priority that is runnable immediately preempts all other tasks, and the task priority does not change […]


Real-time scheduling: assigning priorities

Real-time scheduling in practice In one of our previous items we talked about Real-time scheduling. Now, we want to show how priorities could be assigned in practice and how deterministic system response can be designed. Deterministic response needs to take into account the worst case scenario: everything is happening at once, at the worst possible […]


Real-time scheduling

Definition A real-time operating system is a system that schedules execution of tasks in a timely deterministic manner, and is scalable. The scheduler follows a set of algorithms that determine which task executes at each moment. Preemptive priority-based scheduling is a mandatory property of the operating systems we evaluate for use in our application. A […]