Engineering topics

Pierce, J. L.

Publications and source records attributed to Pierce, J. L..

3 records

NASA NTRS1986

Interface Program for Reliability Predictions

CARE3MENU generates input file for CARE III program. Used to predict reliabilities of complex, redundant, fault-tolerant systems, including digital computers, aircraft, and nuclear and chemical control systems. CARE III input file often becomes complicated and not easily formatted with text editor. Provides easy interactive method of creating input file by automatically formatting set of user-supplied inputs for CARE III system. CARE3MENU provides detailed online help for most of its screen formats.

Bavuso, S. J.↗

NASA NTRS1986

An experiment in software reliability

The results of a software reliability experiment conducted in a controlled laboratory setting are reported. The experiment was undertaken to gather data on software failures and is one in a series of experiments being pursued by the Fault Tolerant Systems Branch of NASA Langley Research Center to find a means of credibly performing reliability evaluations of flight control software. The experiment tests a small sample of implementations of radar tracking software having ultra-reliability requirements and uses n-version programming for error detection, and repetitive run modeling for failure and fault rate estimation. The experiment results agree with those of Nagel and Skrivan in that the program error rates suggest an approximate log-linear pattern and the individual faults occurred with significantly different error rates. Additional analysis of the experimental data raises new questions concerning the phenomenon of interacting faults. This phenomenon may provide one explanation for software reliability decay.

Dunham, J. R.↗

NASA NTRS1986

An empirical study of flight control software reliability

The results of a laboratory experiment in flight control software reliability are reported. The experiment tests a small sample of implementations of a pitch axis control law for a PA28 aircraft with over 14 million pitch commands with varying levels of additive input and feedback noise. The testing which uses the method of n-version programming for error detection surfaced four software faults in one implementation of the control law. The small number of detected faults precluded the conduct of the error burst analyses. The pitch axis problem provides data for use in constructing a model in the prediction of the reliability of software in systems with feedback. The study is undertaken to find means to perform reliability evaluations of flight control software.

Dunham, J. R.↗