Top down, bottom up structured programming and program structuring

New design and programming techniques for shuttle software. Based on previous Apollo experience, recommendations are made to apply top-down structured programming techniques to shuttle software. New software verification techniques for large software systems are recommended. HAL, the higher order language selected for the shuttle flight code, is discussed and found to be adequate for implementing these techniques. Recommendations are made to apply the workable combination of top-down, bottom-up methods in the management of shuttle software. Program structuring is discussed relevant to both programming and management techniques

Unbounded safety verification for hardware using software analyzers

Demand for scalable hardware verification is ever-increasing. We propose an unbounded safety verification framework for hardware, at the heart of which is a software verifier. To this end, we synthesize Verilog at register transfer level into a software-netlist, represented as a word-level ANSI-C program. The proposed tool flow allows us to leverage the precision and scalability of state-of-the-art software verification techniques. In particular, we evaluate unbounded proof techniques, such as predicate abstraction, k-induction, interpolation, and IC3/PDR; and we compare the performance of verification tools from the hardware and software domains that use these techniques. To the best of our knowledge, this is the first attempt to perform unbounded verification of hardware using software analyzers

Man-rated flight software for the F-8 DFBW program

The design, implementation, and verification of the flight control software used in the F-8 DFBW program are discussed. Since the DFBW utilizes an Apollo computer and hardware, the procedures, controls, and basic management techniques employed are based on those developed for the Apollo software system. Program assembly control, simulator configuration control, erasable-memory load generation, change procedures and anomaly reporting are discussed. The primary verification tools are described, as well as the program test plans and their implementation on the various simulators. Failure effects analysis and the creation of special failure generating software for testing purposes are described

Estimating the maximum rise in temperature according to climate models using abstract interpretation

Current climate models are complex computer programs that are typically iterated time-step by time-step to predict the next set of values of the climate-related variables. Since these iterative methods are necessarily computed only for a fixed number of iterations, they are unable to answer the natural question whether there is a limit to the rise of global temperature. In order to answer that question we propose to combine climate models with software verification techniques that can find invariant conditions for the set of program variables. In particular, we apply the constraint database approach to software verification to find that the rise in global temperature is bounded according to the common Java Climate Model that implements the Wigely/Raper Upwelling-Diffusion Energy Balance Model climate model