SOFTWARE SYSTEM SAFETY HANDBOOK: A Technical & Managerial Team Approach

Joint Software System Safety Committee SOFTWARE SYSTEM SAFETY HANDBOOK A Technical & Managerial Team Approach December 1999 This Handbook was funded and developed by the Joint Services Computer Resources Management Group, U.S. Navy, U.S. Army, and the U.S. Air Force Under the direction and guidance of the Joint Services Software Safety Committee of the Joint Services System Safety Panel and the Electronic Industries Association, G-48 Committee AUTHORS David Alberico John Bozarth Michael Brown Janet Gill Steven Mattern Arch McKinlay VI Contributing (Former Chairman) Contributing Contributing (Current Chairman) Contributing Contributing and Integrating Contributing This Handbook represents the cumulative effort of many people. It underwent several reviews by the technical community that resulted in numerous changes to the original draft. Therefore, the contributors are too numerous to list. However, the Joint Services Software System Safety Committee wishes to acknowledge the contributions of the contributing authors to the Handbook. Special thanks to Lt. Col. David Alberico, USAF (RET), Air Force Safety Center, Chair- person of the JSSSSC, from 1995 to 1998, for his initial guidance and contributions in the development of the Handbook. The following authors wrote significant portions of the current Handbook: John Bozarth, CSP, EG&G Technical Services, Dahlgren, VA Michael Brown, Naval Surface Warfare Center, Dahlgren Division, (Chairperson, JSSSSC, 1998 to Present) Janet Gill, Naval Air Warfare Center, Aircraft Division, Patuxent River, MD Steven Mattern, Science and Engineering Associates, Albuquerque, NM Archibald McKinlay, Booz-Allen and Hamilton, St. Louis, MO Other contributing authors: Brenda Hyland, Naval Air Warfare Center, Aircraft Division, Patuxent River, MD Lenny Russo, U.S. Army Communication & Engineering Command, Ft. Monmouth, NJ The committee would also like to thank the following individuals for their specific contributions: Edward Kratovil, Naval Ordnance Safety and Security Activity, Indian Head, MD Craig Schilders, Naval Facilities Command, Washington, DC Benny Smith, U.S. Coast Guard, Washington, DC Steve Smith, Federal Aviation Administration, Washington, DC Lud Sorrentino, Booz-Allen and Hamilton, Dahlgren, VA Norma Stopyra, Naval Space and Warfare Systems Command, San Diego, CA Dennis Rilling, Naval Space and Warfare Systems Command, San Diego, CA Benny White, National Aeronautics and Space Administration, Washington, DC Martin Sullivan, EG&G Technical Services, Dahlgren, VA This Handbook is the result of the contributions of the above mentioned individuals and the extensive review comments from many others. The committee thanks all of the authors and the contributors for their assistance in the development of this Handbook. Software System Safety Handbook Table of Contents TABLE OF CONTENTS 1. EXECUTIVE OVERVIEW.................................................................................................1–1 2. INTRODUCTION TO THE HANDBOOK ........................................................................2–1 2.1 Introduction.....................................................................................................................2–1 2.2 Purpose............................................................................................................................2–2 2.3 Scope...............................................................................................................................2–2 2.4 Authority/Standards.........................................................................................................2–3 2.4.1 Department of Defense..............................................................................................2–3 2.4.1.1 DODD 5000.1.....................................................................................................2–3 2.4.1.2 DOD 5000.2R......................................................................................................2–4 2.4.1.3 Military Standards...............................................................................................2–4 2.4.2 Other Government Agencies.....................................................................................2–8 2.4.2.1 Department of Transportation.............................................................................2–8 2.4.2.2 National Aeronautics and Space Administration..............................................2–11 2.4.3 Commercial.............................................................................................................2–11 2.4.3.1 Institute of Electrical and Electronic Engineering.............................................2–12 2.4.3.2 Electronic Industries Association......................................................................2–12 2.4.3.3 International Electrotechnical Commission ......................................................2–12 2.5 International Standards..................................................................................................2–13 2.5.1 Australian Defense Standard DEF(AUST) 5679 ....................................................2–13 2.5.2 United Kingdom Defense Standard 00-55 & 00-54................................................2–14 2.5.3 United Kingdom Defense Standard 00-56..............................................................2–14 2.6 Handbook Overview .....................................................................................................2–15 2.6.1 Historical Background.............................................................................................2–15 2.6.2 Problem Identification.............................................................................................2–15 2.6.2.1 Within System Safety........................................................................................2–16 2.6.2.2 Within Software Development..........................................................................2–17 2.6.3 Management Responsibilities .................................................................................2–18 2.6.4 Introduction to the “Systems” Approach.................................................................2–18 2.6.4.1 The Hardware Development Life Cycle............................................................2–19 2.6.4.2 The Software Development Life Cycle.............................................................2–20 2.6.4.3 The Integration of Hardware and Software Life Cycles....................................2–24 2.6.5 A “Team” Solution..................................................................................................2–25 2.7 Handbook Organization ................................................................................................2–26 2.7.1 Planning and Management......................................................................................2–28 2.7.2 Task Implementation...............................................................................................2–28 2.7.3 Software Risk Assessment and Acceptance............................................................2–29 2.7.4 Supplementary Appendices.....................................................................................2–29 3. INTRODUCTION TO RISK MANAGEMENT AND SYSTEM SAFETY.......................3–1 3.1 Introduction.....................................................................................................................3–1 3.2 A Discussion of Risk.......................................................................................................3–1 i Software System Safety Handbook Table of Contents 3.3 Types of Risk...................................................................................................................3–2 3.4 Areas of Program Risk....................................................................................................3–3 3.4.1 Schedule Risk............................................................................................................3–5 3.4.2 Budget Risk...............................................................................................................3–6 3.4.3 Sociopolitical Risk....................................................................................................3–7 3.4.4 Technical Risk...........................................................................................................3–7 3.5 System Safety Engineering..............................................................................................3–8 3.6 Safety Risk Management...............................................................................................3–11 3.6.1 Initial Safety Risk Assessment................................................................................3–12 3.6.1.1 Hazard and Failure Mode Identification............................................................3–12 3.6.1.2 Hazard Severity.................................................................................................3–12 3.6.1.3 Hazard Probability.............................................................................................3–13 3.6.1.4 HRI Matrix........................................................................................................3–14 3.6.2 Safety Order of Precedence.....................................................................................3–15 3.6.3 Elimination or Risk Reduction................................................................................3–16 3.6.4 Quantification of Residual Safety Risk...................................................................3–17 3.6.5 Managing and Assuming Residual Safety Risk......................................................3–18 4. SOFTWARE SAFETY ENGINEERING............................................................................4–1 4.1 Introduction.....................................................................................................................4–1 4.1.1 Section 4 Format .......................................................................................................4–3 4.1.2 Process Charts...........................................................................................................4–3 4.1.3 Software Safety Engineering Products......................................................................4–5 4.2 Software Safety Planning Management ..........................................................................4–5 4.2.1 Planning.....................................................................................................................4–6 4.2.1.1 Establish the System Safety Program................................................................4–10 4.2.1.2 Defining Acceptable Levels of Risk..................................................................4–11 4.2.1.3 Program Interfaces.............................................................................................4–12 4.2.1.4 Contract Deliverables........................................................................................4–16 4.2.1.5 Develop Software Hazard Criticality Matrix ....................................................4–17 4.2.2 Management............................................................................................................4–21 4.3 Software Safety Task Implementation ..........................................................................4–25 4.3.1 Software Safety Program Milestones......................................................................4–26 4.3.1 Preliminary Hazard List Development....................................................................4–28 4.3.2 Tailoring Generic Safety-Critical Requirements.....................................................4–31 4.3.3 Preliminary Hazard Analysis Development............................................................4–33 4.3.4 Derive System Safety-Critical Software Requirements ..........................................4–37 4.3.4.1 Preliminary Software Safety Requirements ......................................................4–39 4.3.4.2 Matured Software Safety Requirements............................................................4–40 4.3.4.3 Documenting Software Safety Requirements ...................................................4–40 4.3.4.4 Software Analysis Folders.................................................................................4–41 4.3.5 Preliminary Software Design, Subsystem Hazard Analysis....................................4–42 4.3.5.1 Module Safety-Criticality Analysis...................................................................4–45 4.3.5.2 Program Structure Analysis...............................................................................4–45 4.3.5.3 Traceability Analysis.........................................................................................4–46 ii ... - tailieumienphi.vn