What is called a deterministic system? How is it related to RTOS?

What is called a deterministic system? How is it related to RTOS? A deterministic or determinism system is a system in which a given initial state or condition produces the same output. The output can be determined and there is no randomness or variation in the ways inputs produce outputs.

You are deterministic about what output will be produced and can be sure of that a certain event or action will be performed next without any doubt. That’s why these systems are called deterministic systems.

While deterministic refers to the quality of a system, the term determinism is a state. So, when discussing systems, the more appropriate term is “deterministic system”.

How is a deterministic system different from a nondeterministic system?

A non-deterministic system means there will be randomness in results or outputs and you cannot be ever 100 percent sure about which event or task will be executed next. Hence, a deterministic system can be considered contrary to a nondeterministic system.

With a deterministic system, you know what will happen next or what output to expect. For instance, probabilistic

computing involves taking inputs and subjecting them to probabilistic models in order to guess results.

Through iterative processes, machine learning models can do that with the help of algorithms that constantly adapt and evolve to provide more sophisticated results. In deterministic programming, if X always equals X, you will always get the action Y. However, in non-deterministic programming, there will be an array of output actions to input X. How is a deterministic system related to RTOS? A real-time operating system (RTOS) is itself a deterministic system, which means that it allows you to control what events will execute next and in what fashion.

It is specifically designed to provide a predictable (or deterministic) execution pattern. It is the scheduler algorithm that determines which program to run and when.

In an RTOS, the scheduler is developed in a way it provides a predictable output pattern, which is particularly important for embedded systems because these systems often have real-time requirements. A real-time requirement is one that specifies that the embedded system must respond to a specific event within a strictly defined time i.e. the deadline.

This guarantee can be made only if the behaviour of an operating system can be predicted or deterministic. This is possible only if that operating system is a real-time operating system. Previously, RTOS was designed to run on a microcontroller, which limited the use of RTOS to only microcontroller applications. Thanks to technological

advancements, now, you can get a deterministic or determinism system (RTOS) that can run on a PC along with your traditional operating system, expanding the applications of RTOS. When Windows operating system is used to develop a machine controller, it requires to be extended with an RTOS, which creates a Windows real-time operating system environment.

Other deterministic components in addition to the scheduler include:    

Symmetric multiprocessing Function library Context switch time · Memory management

Typically, an RTOS is widely used in an array of applications, such as control systems, image processing, and motion control. If you use RTOS alongside Windows, you will not only be able to do all the functions related to RTOS but also all other functions that Windows is used for.

For the user, a non-deterministic program can be confusing and frustrating for developers as it makes it hard to test and debug.

For real time determinism, you need an RTOS that works with Windows and ensures deterministic processing within

the Windows platform. The result is usually improved robustness and reliability.

Hard real time deterministic systems guarantee increased safety and reliability.