Conferences and supporting programme
Missing Relationship Between Software FTAs and System FTA on Multi-Core Platforms - Identification and Resolving
The primary objective of applying safety analysis on software architectural design is to anticipate potential scenarios of failure. This kind of analysis aims to identify how failures originate at the low-levels of the design and how combinations or sequences of such low-level failures propagate to higher levels leading to a safety goal violation. Such described analysis can be realized by applying software Fault Tree Analysis (FTA) method. This paper will discuss how the software FTA will be performed on multi-core target taking into consideration the inter-dependencies between the cores; it also will discuss the linkage of these software FTAs with system FTA to reach a consistent safety analysis. In general, the FTA works on a set of Top Level Events (TLEs) that represent the failure events in which affect the critical system outputs. Then it traces these events till their root causes which are known as Basic Events (BEs). After defining these BEs, a list of safety mechanisms is provided to tolerate those failures. On multi-core platform, FTA is usually performed separately on each core ignoring the inter-dependencies between them during the software safety analysis phase. The major challenge is how to cover the possible failures resulting from these inter-dependencies between the different cores with additional safety mechanisms. Another important challenge is to identify the relation between different applied safety analyses (e.g. system FTA and software FTA) to have a consistently integrated FTA. The proposed solution starts with performing the software FTA on each core separately as usual. Because of their inter-dependencies, a complementary step is needed to identify the critical data transferred between them. If the data transferred between cores is used in a safety critical functionality in the receiving core then it will be considered as a BE. Accordingly, a new TLE shall be defined in the transmitting core and considered in the software FTA of this core. Finally, the relationship between the software FTAs of different cores is illustrated in the whole FTA diagram.
--- Date: 28.02.2018 Time: 3:00 PM - 3:30 PM Location: Conference Counter NCC Ost