## 1 Introduction
However, despite the continuous increase in the utilization of COTS-based components, their reliable performance in real-time systems still remains under further research, which is an objective of this work too. An important motivation for this research into reliable real-time systems based on COTS components, particularly for control applications in manufacturing, is the continuous increase of the demand for rapid, low-cost, low-consumption, and short-time development. Additionally, there is also a need for the immediate availability of versatile and general-purpose hardware/software components (e.g., cloud computing is the on-demand availability of computer system resources). For this reason, a strong emphasis of this research is to find efficient solutions to relevant open questions and issues, regarding the reliability and efficiency of real-time control systems based on general-purpose hardware/software components, such as:  
* How to ensure availability and reliability through a warehouse of general-purpose hardware/software components? * How to integrate and synthesize complex general-purpose hardware/software components into real-time systems applications? * How to assess and measure the reliability of real-time systems applications based on general-purpose hardware/software components? * How to evaluate the overall performance of real-time systems based on a versatile range of general-purpose components and devices? This research work proposes a versatile integrative design approach and architectural framework (VIDAF) that addresses these challenging issues and open questions, with credible methodologies and approaches that lead to novel efficient solutions, validated in real-world cases. VIDAF defines an open architectural framework in building reliable, real-time, and cost-effective systems and applications, based on general-purpose hardware/software components, and minimizing the use of specialized ones. In resolving these challenges, the research targets the following objectives:  
* Define a novel system architectural framework that uses general-purpose hardware and software components for building reliable real-time and cost-efficient control systems. * Propose a novel system application infrastructure that enables efficient and reliable functionality and implementation of such systems in real-time applications. * Demonstrate the efficient and reliable development and exploitation of such systems based on general-purpose hardware/software, in real-time embedded applications in manufacturing. This research paper presents the approaches and methodology to achieve these objectives and goals in an innovative way, proposes an architectural framework that enables the development and implementation of reliable real-time control systems, and demonstrates its feasibility and applicability through a system application in manufacturing. A COTS-based development process is proposed, upon which a system architecture is implemented into the control of a lime mash/slurry (milk-of-lime) storage and delivery machine. In this case study, a custom-built (80C188 EB-based and assembly driven) controller was substituted successfully with COTS-based hardware components (RaspberryPi-based microcontroller board, referred from now on as RPi3) and open-source control software modules (written in standard C and Python). The experimental results of the architectural working prototype provide evidence that the system performs reasonably well and correctly. Overall, this research work presents a framework with its own structure specifications and constraints, upon which COTS-based systems could be developed, and further on, based on the architectural framework proposed, a case study demonstrates the development of such a COTS-based system in real-time control in manufacturing, verifying its validity and applicability. The proposed architectural framework is just a prototype architecture that could not be generally applied as a roadmap or as a standard in developing real-time COTS-based systems in the manufacturing domain.