460 research outputs found
A Strategy Language for Testing Register Transfer Level Logic
The development of modern ICs requires a huge investment in RTL verification.
This is a reflection of brisk release schedules and the complexity of
contemporary chip designs. A major bottleneck to reaching verification closure
in such designs is the disproportionate effort expended in crafting directed
tests; which is necessary to reach those behaviors that other, more automated
testing methods fail to cover. This paper defines a novel language that can be
used to generate targeted stimuli for RTL logic and which mitigates the
complexities of writing directed tests. The main idea is to treat directed
testing as a meta-reasoning problem about simulation. Our language is both
formalized and prototyped as a proof-search strategy language in rewriting
logic. We illustrate its novel features and practical use with several
examples.published or submitted for publicatio
Towards the formal verification of the requirements and design of a processor interface unit
The formal verification of the design and partial requirements for a Processor Interface Unit (PIU) using the Higher Order Logic (HOL) theorem-proving system is described. The processor interface unit is a single-chip subsystem within a fault-tolerant embedded system under development within the Boeing Defense and Space Group. It provides the opportunity to investigate the specification and verification of a real-world subsystem within a commercially-developed fault-tolerant computer. An overview of the PIU verification effort is given. The actual HOL listing from the verification effort are documented in a companion NASA contractor report entitled 'Towards the Formal Verification of the Requirements and Design of a Processor Interface Unit - HOL Listings' including the general-purpose HOL theories and definitions that support the PIU verification as well as tactics used in the proofs
Software Verification for Weak Memory via Program Transformation
Despite multiprocessors implementing weak memory models, verification methods
often assume Sequential Consistency (SC), thus may miss bugs due to weak
memory. We propose a sound transformation of the program to verify, enabling SC
tools to perform verification w.r.t. weak memory. We present experiments for a
broad variety of models (from x86/TSO to Power/ARM) and a vast range of
verification tools, quantify the additional cost of the transformation and
highlight the cases when we can drastically reduce it. Our benchmarks include
work-queue management code from PostgreSQL
Copilot: Monitoring Embedded Systems
Runtime verification (RV) is a natural fit for ultra-critical systems, where correctness is imperative. In ultra-critical systems, even if the software is fault-free, because of the inherent unreliability of commodity hardware and the adversity of operational environments, processing units (and their hosted software) are replicated, and fault-tolerant algorithms are used to compare the outputs. We investigate both software monitoring in distributed fault-tolerant systems, as well as implementing fault-tolerance mechanisms using RV techniques. We describe the Copilot language and compiler, specifically designed for generating monitors for distributed, hard real-time systems. We also describe two case-studies in which we generated Copilot monitors in avionics systems
The (Un)detectability of Absolute Newtonian Masses
Absolutism about mass claims that mass ratios obtain in virtue of absolute masses. Comparativism denies this. Dasgupta (2013) argues for comparativism about mass, in the context of Newtonian Gravity. Such an argument requires proving that comparativism is empirically adequate. Dasgupta equates this to showing that absolute masses are undetectable, and attempts to do so. This paper develops an argument by Baker to the contrary: absolute masses are in fact empirically meaningful, that is detectable (in some weak sense). Additionally, it is argued that the requirement of empirical adequacy should not be cashed out in terms of undetectability in the first place. The paper closes by sketching the possible strategies that remain for the comparativist. Along the way a framework is developed that is useful for thinking about these issues: Ozma games---how could one explain to an alien civilisation what an absolute mass is
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