1、July 18, 2001Mission Success Begins With SafetyQuality Leadership ForumSoftware Quality Assurance at GSFCDr. Linda H. RosenbergChief Scientist for Software AssuranceOffice of Systems Safety and Mission Assurance301-286-0087Linda.Rosenberggsfc.nasa.gov. . .July 18, 2001Mission Success Begins With Saf
2、etyDiscussion AreasNASA Software ActivitiesSoftware Working GroupNASA Software Initiative Implementation PlanGSFC Software Assurance ActivitiesSoftware Process Improvement CMMISoftware Safety and ReliabilitySoftware Quality MetricsIV&V. . .July 18, 2001Mission Success Begins With Safety. . .July 18,
3、 2001Mission Success Begins With SafetySWG Initial Tasks1 - Define criteria for use of IV&V on a project2 - Standards evaluation Review IEEE 12207 for potential NASA use Review draft of NPG 2820 Review draft NPD for IV&V3 - Prepare a plan for improving software process Implementation of software met
4、rics program Implementation of process improvement model Establishment of Center Software Engineering Process Groups (SEPG). . .July 18, 2001Mission Success Begins With SafetySWG Task 3 - MetricsSet of metrics finalized summer 2000Objectives Provide project managers with usable informationProvide ag
5、ency with information on software trendsProvide a measure to assess improvement2 test projects per Center started Fall 2000 for 1 year(GSFC projects AURA & AQUA)Developing database for metrics entry and analysis. . .July 18, 2001Mission Success Begins With SafetyNASA Software Initiative Implementati
6、on PlanGoal: Advance software engineering practices (development, assurance, and management) to effectively deliver the scientific and technological objectives of NASA.Strategies:1. Develop and implement Agency-wide and Center plans for continuous software process and product improvement in NASA and
7、 Contractor developed software; also establish infrastructure and measurement system2. Improve safety, reliability, and quality of software products through the integration of sound software engineering principles and standards.3. Provide input for research based on identified software problem areas
8、 and infuse research results4. Improve software engineering knowledge base in NASA, and implement strategies for attracting, retaining software engineers. . .July 18, 2001Mission Success Begins With Safety. . .July 18, 2001Mission Success Begins With SafetyGSFC Software Development Process Improveme
9、ntPurpose - improving the processes and practices in use at GSFC using the Capability Maturity Model Integrated (CMMI) levels of maturity (ML) as a measure of progress. Scope - process improvement effort that will be undertaken with the goal of raising GSFC from its current state to a CMMI Defined m
10、aturity level (L3). All projects defined by NPG 7120.5 or otherwise identified by GSFCs Center Director will participate in this effort. . . .July 18, 2001Mission Success Begins With SafetyCapability Maturity Model Integrated (CMMI)LevelProcess AreasOrganization innovation and deploymentCausal analy
11、sis and resolutionOrganizational process performanceQuantitative project managementRequirements developmentTechnical solutionProduct integrationVerificationValidationOrganizational process focusOrganizational process definitionOrganizational trainingIntegrated project managementRisk managementDecisi
12、on analysis and resolutionRequirements managementProject planningProject monitoring and controlSupplier agreement managementMeasurement and analysis5 Optimizing4 QuantitativelyManaged3 Defined2 Managed1 InitialSoftwareDevelopmentSWSystemsSESoftware AcquisitionSACMMIFor Pilots:Emphasis - SW CMMAs app
13、ropriate - SE CMM SA CMMGSFCGOAL. . .July 18, 2001Mission Success Begins With SafetyPilot Project SelectionProject WFLT SWGND SWInstr 1Instr 2Project XFLT SWGND SWInstr 1Instr 2Project YFLT SWGND SWInstr 1Instr 2Project ZFLT SWGND SWInstr 1Instr 2. . .July 18, 2001Mission Success Begins With SafetyS
14、cheduleGSFC Implementation plan to HQ July 2001Management Oversight GroupMember identification July 2001Initial meeting August 2001Training in CMMI September (1/2 day or 3 day option)Engineering Process GroupMember identification July 2001Training in CMMI September 2001(3 day course)Training in Risk
15、 Management October 2001Pilot ImplementationPilot identification by October 1, 2001Pilot study complete October 1, 2002Evaluation of Pilot and roll out January 1, 2003. . .July 18, 2001Mission Success Begins With SafetyWhat is meant by “safety”A system/product is Safe when:There is little to no chan
16、ce for it to blow up, break, malfunction, or otherwise fail in such a way as to potentially injure someone Something is Critical when there is a potential for:Serious injury or deathSerious impact to the bottom line, or Bad publicity, public reputationVital information is accessible to the wrong fol
17、ksA system/product is Not Safe when:Someone could die or be seriously injuredNASA includes possible destruction of vital equipment as well. . .July 18, 2001Mission Success Begins With SafetyStandardsNASA Standards (http:/standards.nasa.gov/sitemap.htm)NPG 8715.3NASA Safety Manual NSTS-1700-7B Safety
18、 Policy and Requirements for Payloads (Shuttle and ISS) NASA-STD-8719.13ANASA Software Safety Standard NASA-GB-A302 Software Formal Inspections Guidebook NSTS-22254 Methodology for Conduct of Space Shuttle Program Hazard Analyses SSP-50038 Computer-Based Control System Safety Requirements, ISS Progr
19、amNPD/NPG 8730 “NASA IV&V Processes “IEEE StandardsIEEE 12207 Information Technology - Software Life Cycle Processes IEEE 830-1998 Recommended Practice for Software Requirements SpecificationsIEEE 1016-1998 Recommended Practice for Software Design DescriptionsIEEE 1228-1994 Standard for Software Saf
20、ety Plans Other StandardsMIL-STD-882D System Safety Program Requirements (C version January 19, 1993)DO-178B Software Considerations in Airborne Systems and Equipment Certification (Federal Aviation Administration).ISO 9000-3Guidelines For The Application Of ISO 9001 To The Development, Supply, Inst
21、allation And Maintenance Of Computer Software. . .July 18, 2001Mission Success Begins With SafetySoftware ReliabilityThe probability that software will not cause the failure of a system for a specified time under specified conditions. The probability is a function of the inputs to and use of the sys
22、tem, as well as a function of the existence of faults in the software. The inputs to the system determine whether existing faults, if any, are encountered. AIAA IEEE 982 IEEE 982.1-1988 Software Reliability Management : “The process of optimizing the reliability of software through a program that em
23、phasizes software error prevention, fault detection and removal, and the use of measurements to maximize reliability in light of project constraints such as resources, schedule and performance.”. . .July 18, 2001Mission Success Begins With SafetyHardware vs. Software ReliabilityBurn in Useful Life W
24、ear outIntegration Useful Life Obsolete & testHardware Failure RateSoftware Failure RateHardware reliability = Software reliability. . .July 18, 2001Mission Success Begins With SafetyDefinitions: Safe vs. ReliableA system is:safe if it doesnt kill anyone, or the system itself, while either performin
25、g its normal operations or, when unable to perform correctly, “fails-safe” .reliable if it performs the required functions within specified parameters/environment and within predicted working timeframe consistentlySome consider Software to be very reliable, in that it does just what its programmed t
26、o do, over and over and over again. It doesnt wear out or break. However, Linda will give you the real picture on Software reliability!. . .July 18, 2001Mission Success Begins With SafetyRequirementsHow Do We Assure / Measure Software Quality?DesignCodingTestingCan you test the requirements?Are the
27、requirements complete?Are you testing each requirement?How much testing is necessary?How hard is it to fix the components?Can I reuse any components?What is the quality and complexity of the code?How many errors still remain?What is the reliability?When can I stop testing?. . .July 18, 2001Mission S
28、uccess Begins With SafetyIV&V ApproachReq Design Code Test (Verification & Validation)Unit IntegrationAcceptanceReq Design Code Testing UnitTest (Verification & Validation) Integration AcceptanceClean Room ApproachTraditional Software DevelopmentV&ViV&VReq Design Code Test (Verification & Validation)Unit IntegrationAcceptanceIV&V ImplementationIV&V. . .
