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Open AccessArticle

An N-Modular Redundancy Framework Incorporating Response-Time Analysis on Multiprocessor Platforms

1
Agency for Defense Development (ADD), Defense Satellite Systems PMO, Daejeon 34063, Korea
2
Agency for Defense Development (ADD), The 3rd R&D Institute-3rd Directorate, Daejeon 34063, Korea
3
Department of Computer Science and Engineering, Incheon National University (INU), Incheon 22012, Korea
*
Author to whom correspondence should be addressed.
Symmetry 2019, 11(8), 960; https://doi.org/10.3390/sym11080960
Received: 8 July 2019 / Revised: 22 July 2019 / Accepted: 27 July 2019 / Published: 31 July 2019
A timing constraint and a high level of reliability are the fundamental requirements for designing hard real-time systems. To support both requirements, the N modular redundancy (NMR) technique as a fault-tolerant real-time scheduling has been proposed, which executes identical copies for each task simultaneously on multiprocessor platforms, and a single correct one is voted on, if any. However, this technique can compromise the schedulability of the target system during improving reliability because it produces N identical copies of each job that execute in parallel on multiprocessor platforms, and some tasks may miss their deadlines due to the enlarged computing power required for completing their executions. In this paper, we propose task-level N modular redundancy (TL-NMR), which improves the system reliability of the target system of which tasks are scheduled by any fixed-priority (FP) scheduling without schedulability loss. Based on experimental results, we demonstrate that TL-NMR maintains the schedulability, while significantly improving average system safety compared to the existing NMR. View Full-Text
Keywords: hard real-time systems; schedulability; reliability; N modular redundancy; multiprocessor platform; fixed-priority scheduling hard real-time systems; schedulability; reliability; N modular redundancy; multiprocessor platform; fixed-priority scheduling
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Baek, J.; Baek, J.; Yoo, J.; Baek, H. An N-Modular Redundancy Framework Incorporating Response-Time Analysis on Multiprocessor Platforms. Symmetry 2019, 11, 960.

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