NASA IV&V Facility Software Independent Verification and Validation (IV&V) NASA IV&V Facility Fairmont, West Virginia Judith N. Bruner Acting Director

NASA IV&V Facility Content Why are we discussing IV&V? What is IV&V? How is IV&V done? IV&V process Why perform IV&V? Summary Points of Contact

NASA IV&V Facility Why are we discussing IV&V?

NASA IV&V Facility Setting the Stage In the 90s, the Commanding General of theArmy’s Operational Test and Evaluation Agency noted that 90 percent of systems that were not ready for scheduled operational tests had been delayed by immature software.

NASA IV&V Facility Software “Chaos” 16% Successful - In Budget - On Time - Meets Requirements - User involved 31% Cancelled - Development 53% “Challenged” - Over budget by 189% - Late by 222% - Missing 39% of Capabilities Note: For Large Companies - 9% were Successful % Challenged - Over budget by 178% - Late by 230% - Missing 58% of Capabilities % were Cancelled The Standish Group examined 8,380 Software Projects.

NASA IV&V Facility Error Densities 68% 9% 23% Requirements Specification Installation & Commissioning Design & Implementation

NASA IV&V Facility Increasing Cost of Changes (Normalized to Requirements Phase) The cost to correct an software error multiplies during the development lifecycle. Cost scale factor

NASA IV&V Facility What is IV&V?

NASA IV&V Facility Independent Verification and Validation (IV&V) Independent –Technical: IV&V prioritizes its own efforts –Managerial: Independent reporting route to Program Management –Financial: Budget is allocated by program and controlled at high level such that IV&V effectiveness is not compromised Verification (Are we building the product right?) –The process of determining whether or not the products of a given phase of the software development cycle fulfill the requirements established during the previous phase –Is internally complete, consistent and correct enough to support next phase Validation (Are we building the right product?) –The process of evaluating software throughout its development process to ensure compliance with software requirements. This process ensures: Expected behavior when subjected to anticipated events No unexpected behavior when subjected to unanticipated events System performs to the customer’s expectations under all operational conditions

NASA IV&V Facility Independent Verification & Validation Software IV&V is a systems engineering process employing rigorous methodologies for evaluating the correctness and quality of the software product throughout the software life cycle Adapted to characteristics of the target program

NASA IV&V Facility How is IV&V done?

NASA IV&V Facility IV&V Activities Throughout Lifecycle Requirements Phase System Reqts Analysis S/W Reqts Analysis Interface Analysis Process Analysis Technical Reviews & Audits Design Phase Design Analysis Interface Analysis Test Program Analysis Supportability Analysis Process Analysis Technical Reviews & Audits Code Phase Code Analysis Test Program Analysis Supportability Analysis Process Analysis Technical Reviews & Audits Test Phase Test Program Analysis Independent Test Supportability Analysis Technical Reviews & Audits Verify Validate

NASA IV&V Facility IV&V Life Cycle Functions IV&V Process provides tools and analysis procedures appropriate to each phase of the software development life cycle: –Formulation Phase: Is development process sound, repeatable, and managed? –Requirements Phase: Verify that system and software requirements are correct, complete, traceable and testable Analyze system-level requirements: Are test plans and acceptance criteria sufficient to validate system requirements and operational needs? Are testing methods sufficient to verify and validate software requirements? Are the correct software development, management, and support processes in place? –Design Phase: Does the design support the requirements? Are test plans and test environments sufficient to verify and validate software and operational requirements? Does the design have any characteristics that will cause it to fail under operational scenarios? What solutions are appropriate?

NASA IV&V Facility IV&V Life Cycle Functions (cont.) Typical IV&V functions by Software life-cycle phase (cont.): –Coding Phase: Does the code reflect the design? Is the code correct? Verify that test cases trace to and cover software requirements and operational needs Verify that software test cases, expected results, and evaluation criteria fully meet testing objectives Analyze selected code unit test plans and results to verify full coverage of logic paths, range of input conditions, error handling, etc. –Test Phase: Analyze correct dispositioning of software test anomalies Validate software test results versus acceptance criteria Verify tracing and successful completion of all software test objectives –Operational Phase: Verify that regression tests are sufficient to identify adverse impacts of changes

NASA IV&V Facility IV&V Testing Involvement IV&V identifies deficiencies in program’s test planning Program changes their procedures to address deficiencies vice IV&V independently test IV&V may independently test highly critical software using an IV&V testbed –Whitebox –Stress –Endurance –Limit Developer motivated to show software works IV&V attempts to break software

NASA IV&V Facility IV&V Process

NASA IV&V Facility IV&V Process Integrates IV&V into program Provides IV&V funding Resolves Exception issues Reflects IV&V in program mgmt plan Agrees to data transfer plan Reflects agreement in subcontracts IV&V in phase with development Program Developer IV&V Assessment information IV&V proposal agreement Planning Introduce issues at lowest level Allow developer time to respond Issue resolved Introduce issues at lowest level Allow developer time to respond If no resolution, take issue to program Requirements Design Code Test Exception Normal CARA results Defines IV&V scope and objectives Planning Execute

NASA IV&V Facility IV&V Scope Scope is determined so as to minimize the risk within the Program’s IV&V budget. Effort is based on: –Criticality and risk of system functions performed/managed by software –Budget limitations Program’s IV&V budget SpecificationsProgram goalsDev plans/schedules Criticality Analysis and Risk Assessment Estimate resource requirements Acceptable? Yes IV&V Plan Revise scope: - Breadth vs depth - Exceptions No

NASA IV&V Facility CARA Scoring Methodology Criticality: Catastrophic=4 Critical=3 Moderate=2 Low=1 Performance and Operations Safety Cost/schedule Category Rating Average Criticality Risk: Category High=3 Moderate=2 Low=1 Rating Complexity Technology Maturity Reqts Dfn & Stability Testability Developer Experience Average Risk CARA score For each Software Function: Set IV&V Analysis Level (IAL) Thresholds IALCARA Score None:1 < CARA < 2 Limited (L):2 < CARA < 5 Focused (F):5 < CARA < 8 Comprehensive (C):8 < CARA < 12

NASA IV&V Facility CARA Criticality Sample Criticality Evaluation Criteria

NASA IV&V Facility CARA Risk Sample Risk Driver Criteria

NASA IV&V Facility Requirements Analysis IALs

NASA IV&V Facility Design Analysis IALs

NASA IV&V Facility Code Analysis IALs

NASA IV&V Facility Test Analysis IALs

NASA IV&V Facility IV&V Is Process As Well As Product Oriented Software schedules, development tracking, critical path analysis, configuration mgmt Program processes Ancillary developments Simulations, trainers, test environments Increased probability of success -Good processes allow early error identification and correction -Quality documentation enhances software maintenance

NASA IV&V Facility IV&V Increases Program Awareness Program Identification of top risks Eval of Program Devel status Eval of Program Schedule status Week Month IV&V Status Reviews Reqts Design Phase complete analysis report IV&V is a program level “tool” to efficiently and effectively manage software development risk.

NASA IV&V Facility Staffing Paradigm Developer Site Program Site S/W IV&V Facility Developers IV&V Pgm Mgmt IV&V Eyes, Ears, Advocates, & Domain Experts (Validation) Critical Mass of: - Analysts - Tools

NASA IV&V Facility Why perform IV&V?

NASA IV&V Facility IV&V Benefits Better software/system Performance Higher Confidence in Software Reliability Compliance between Specs & Code Criteria for Program Acceptance Better Visibility into Development Better Decision Criteria Second Source Technical Alternative Reduced maintenance cost Reduced Frequency of Operational Change TechnicalManagement

NASA IV&V Facility Summary

NASA IV&V Facility IV&V Key Points IV&V works with the Project –Goal is project success IV&V is an engineering discipline –IV&V processes are defined and tailored to the specific program –Mission, operations and systems knowledge is used to perform engineering analyses of system components IV&V is most effective when started early –70% of errors found in testing are traceable to problems in the requirements and design IV&V works problems at the lowest possible level –Primarily work via established informal interfaces with the development organization - working groups, IPTs, etc. –Elevate issues only when necessary

NASA IV&V Facility IV&V Approach Efficiently Mitigates Risk It is not necessary or feasible to perform all IV&V analyses on all software functions IV&V resources allocated to reduce overall exposure to operational, development, and cost/schedule risks –Software functions with higher cirticality and development risk receive enhanced levels of analysis (‘CARA’ process) –Systems analyses performed to reduce costly interface and integration problems –Process analyses performed to verify ability to produce desired result relative to program plans, needs and goals IV&V working interfaces promote timely problem resolution –Proactive participation on pertinent development teams –Emphasis on early identification of technical problems –Engineering recommendations provided to expedite solution development and implementation

NASA IV&V Facility Analyses Are Value Added and Complementary - Not Duplicative Analyses performed from a systems perspective considering mission needs and system use, hazards and interfaces –Discipline experts assigned to perform analysis across all life cycle phases –Horizontal specialty skills are matrixed across IV&V functional teams to verify correct systems integration –Specialized tools and simulations perform complex analyses IV&V testing activities complement developer testing enhancing overall software confidence –Developer testing focuses on demonstrating nominal behavior, IV&V testing activities try to break the software Overall program integration, test and verification approach analyzed for completeness, integrity and effectiveness

NASA IV&V Facility Why use NASA IV&V Facility? Software IV&V, as practiced by the NASA Software IV&V Facility, is a well-defined, proven, systems engineering discipline designed to reduce the risk in major software developments.

NASA IV&V Facility NASA IV&V Facility Points of Contact Judy Bruner Acting Director Bill Jackson Deputy Director