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Tolerating hardware faults in modern architectures is becoming a prominent problem due to the miniaturization of the hardware components, their increasing complexity, and the necessity to reduce costs. Software-Implemented Hardware Fault Tolerance approaches have been developed to improve system dependability regarding hardware faults without resorting to custom hardware solutions. However, these come at the expense of making the satisfaction of the timing constraints of the applications/activities harder from a scheduling standpoint. This article surveys the current state-of-the-art of fault tolerance approaches when used in the context of real-time systems, identifying the main challenges and the cross-links between these two topics. We propose a joint scheduling-failure analysis model that highlights the formal interactions among software fault tolerance mechanisms and timing properties. This model allows us to present and discuss many open research questions with the final aim to spur future research activities.
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FLYOS: Integrated Modular Avionics for Autonomous Multicopters
Autonomous multicopters often feature federated architectures, which incur relatively high communication costs between separate hardware components. These costs limit the ability to react quickly to new mission objectives. Additionally, federated architectures are not easily upgraded without introducing new hardware that impacts size, weight, power and cost (SWaP-C) constraints. In turn, such constraints restrict the use of redundant hardware to handle faults. In response to these challenges, we propose FlyOS, an Integrated Modular Avionics (IMA) approach to consolidate mixed-criticality flight functions in software on heterogeneous multicore aerial platforms. FlyOS is based on a separation kernel that statically partitions resources among virtualized sandboxed OSes. We present a dual-sandbox prototype configuration, where timing-and safety-critical flight control tasks execute in a real-time OS alongside mission-critical vision-based navigation tasks in a Linux sandbox. Low latency shared memory communication allows flight commands and data to be relayed in real-time between sandboxes. A hypervisor-based fault-tolerance mechanism is also deployed to ensure failover flight control in case of critical function or timing failures. We validate FlyOS’s performance and showcase its benefits when compared against traditional architectures in terms of predictable, extensible and efficient flight control.
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- Award ID(s):
- 2007707
- PAR ID:
- 10355461
- Date Published:
- Journal Name:
- IEEE 28th Real-Time and Embedded Technology and Applications Symposium (RTAS)
- Page Range / eLocation ID:
- 68 to 81
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1109/RTAS54340.2022.00014
