ISSRE Keynote: Russell W. Morris

Technical Fellow
Reliability, Maintainability & Systems Health
The Boeing Company, Seattle

Software Reliability - 40 years of avoiding the question (Slides)

During the last 40 years, there has been an explosion of technical complexity of both hardware and software. Hardware, characterized by physics and empirical data, provides the reliability and systems engineers with a capability to estimate the expected reliability. Software has however managed to avoid this type of model development in part because the factors affecting reliability are not measureable by physical data. Software reliability is characterized by data gathered during systems integration and test. This data has attributes and parameters such as defect density, capability of programming of the software engineering team, the experience of the engineering team, the understanding of the application be the designers, the language used and more. Models developed by J. Musa, N. F. Schneidewind, B. Littlewood, K. Okumoto, et al, make use of both target platform characteristics as well as the history of the product as it proceeds through the design, and systems test and integration. The latter is the one element that has the most significant impact on the reliability of the final product, and is the one that has the least amount of supplier data. Software reliability is more than the processes advocated by CMMI (Capability Maturity Model® Integration) and is susceptible to esoteric and infinitely harder parameters to measure. Many suppliers do not keep data on the development metrics that provide insight into the reliability of their product. This greatly affects the reliability of products such as commercial off the shelf (COTs) equipment. The author discusses some of the elements that affect software reliability and compares some of the differences when trying to estimate reliability of today's systems.


Russell Morris is one of the top experts in Systems Reliability, Maintainability and System Health (RM&SH) for The Boeing Company. Russ has 9 years as a designer of servo systems, phased array medical diagnostic ultrasound and digital subtraction angiography, low noise amplifiers, and broadcast quality television. He has worked the past 23 years in Aerospace Reliability and Maintainability. His work spans all aspects of the company product lines and divisions' hardware and software including commercial aircraft, solar array power generation, military systems as well as being a mentor and teacher in the R&M specialty. He is a past chairperson for the SAE National G-11 Reliability Committee and contributor to the SAE JA 1000 series of R&M national standards. He is a recognized individual contributor for a large number of Boeing programs including Unmanned Aircraft (such as Darkstar, UCAV and HALE), Launch Vehicles (RLV, EELV), Sea Launch, Future Combat Systems, Ground Mid-Course Defense, and commercial aircraft (777, 787). He has published several papers nationally and authored a number of internal papers on modeling, analysis and processes for R&M. Russ has a BSEE from San Jose State University (San Jose California). He has one patent and 3 patents in process.