Piotr Gawkowski

Software Implemented Fault Inserters

Abstract The paper deals with the problem of checking system fault susceptibility in simulation experiments. Three fault simulators are presented. They are based on the idea of disturbing system states (registers, memory locations). Two systems deal with Win 32 environment and one with Linux. They differ in implementation and functional capabilities. The use of fault injection in system dependability evaluation is illustrated in a sample of experiments.

Analyzing Fault Susceptibility of ABS Microcontroller

In real-time safety-critical systems, it is important to predict the impact of faults on their operation. For this purpose we have developed a test bed based on software implemented fault injection (SWIFI). Faults are simulated by disturbing the states of registers and memory cells. Analyzing reactive and embedded systems with SWIFI tools is a new challenge related to the simulation of an external environment for the system, designing test scenarios and result qualification. The paper presents our original approach to these problems verified for an ABS microcontroller. We show fault susceptibility of the ABS microcontroller and outline software techniques to increase fault robustness.

Analyzing the effectiveness of fault hardening procedures

The paper addresses the problem of evaluating the effectiveness of fault hardening procedures based on software redundancy. We analyze the time and memory overhead of fine-grained and coarse-grained error detection and correction techniques. We check the impact of the involved overhead on fault coverage. The presented considerations are illustrated with fault injection experimental results.

Developing Fault Injection Environment for Complex Experiments

The paper addresses the problem of creating a comprehensive fault injection environment, which integrates and improves various simulation and supplementary functions. This is illustrated with experimental results.

Software Implementation of Explicit DMC Algorithm with Improved Dependability

The paper presents an approach to improve the dependability of software implementation of the explicit DMC (Dynamic Matrix Control) Model Predictive Control (MPC) algorithm. The investigated DMC algorithm is implemented for a control system of a rectification column - a process with strong cross-couplings and significant time delays. The control plant has two manipulated inputs and two outputs. The fault sensitivity of the proposed implementation is verified in experiments with a software implemented fault injector. The experimental results prove the efficiency of proposed software improvements.

Experimental Evaluation of Fault Handling Mechanisms

The paper deals with the problem of enhancing fault handling capabilities (detection, masking, recovery) in COTS based systems by means of various software techniques. The effectiveness of this approach is analyzed using fault insertion testbed. Discussing test results, we concentrate on fault propagation effects and experiment tuning issues.

An approach to distributed fault injection experiments

Software implemented fault injection technique is gaining much interest in evaluating system dependability. For complex software applications fault injection experiments take a lot of time. In the paper we present an innovative approach to fault injection by performing it in LAN distributed environment. The paper presents the system architecture, task scheduling and the analysis of its effectiveness. The presented considerations are illustrated with practical results.

Tracing fault effects in system environment

The paper presents a new tool (FITS) for fault insertion in Win32 environment. Using processor trace mode operation we assure high accuracy in analyzing fault effects in the system. Moreover we provide some supplementary functions which simplify this process. The productivity of FITS have been illustrated in many experimental results related to the analysis of system sensitivity to hardware faults and evaluation of developed error detection and fault tolerance methods.

Developing Data Warehouse for Simulation Experiments

The paper deals with the problem of creating a specialized data warehouse for collecting and analyzing experimental results, which relate to system dependability evaluation using fault injections into running programs. The developed data warehouse with embedded data mining capabilities facilitates to identify factors influencing fault susceptibility of analyzed applications. The paper presents the developed system, and illustrates its usefulness with a sample of experimental results.

Enhancing Fault Injection Testbench

Fault injection techniques are widely used in system dependability evaluation. In the paper we deal with the problem of enhancing classical fault injection tools in two aspects: improvement of experiment effectiveness and result analysis capabilities. In particular we discuss the problem of distributing fault injection processes within a computer network and collecting the simulation results in a data warehouse with data mining capabilities. The presented considerations are illustrated with some experimental results performed with simulation tools developed in our institute