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Standards - PowerPoint PPT Presentation

avram-caldwell
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Standards

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  1. Standards

  2. What is a standard? • What are the benefits of using a standard? • What are the costs? • Do the costs exceed the benefits?

  3. Definition of standard A technical specification or other document available to the public, drawn up with the cooperation and consensus or general approval of all interests affected by it, based on the consolidated results of science, technology and experience, aimed at the promotion of optimum community benefits • British Standards Institute, 1981

  4. Standards are checklists • (like a pilot’s checklist) • Remind you of things you may forget • Force you to acknowledge the consequences of not doing one of the tasks on the standard • Don’t build the list from scratch: use one built by hundreds or thousands of professionals

  5. Standards outside SE • measures (gallons, liters, mm) • sizing (electrical plugs)

  6. Comparison of Standards External Product Process Resource Internal Product safe pushchairs safe software

  7. Other engineering: guidelines for product evaluation guidelines for acceptable outcomes Software engineering guidelines for process guidelines for techniques few guidelines for product evaluation Comparison of Standards

  8. Software Engineering Standards • Technical specifications available to public • Consensus, but not necessarily of all affected parties (usually by committee) • Not necessarily based on science, technology, or experience • Language standards w/o case studies • Techniques (clean room, OO design) w/o science

  9. Example: 1228-1994 IEEE Standard for Software Safety Plans • Abstract: The minimum acceptable requirements for the content of a software safety plan are established. This standard applies to the software safety plan used for the development, procurement, maintenance, and retirement of safety-critical software. This standard requires that the plan be prepared within the context of the system safety program. Only the safety aspects of the software are included. This standard does not contain special provisions required for software used in distributed systems or in parallel processors

  10. Example: 1008-1987 (R1993) IEEE Standard for Software Unit Testing 1. Scope and References 2. Definitions 3. Unit Testing Activities 3.1 Plan the General Approach, Resources, and Schedule. 3.2 Determine Features To Be Tested 3.3 Refine the General Plan 3.4 Design the Set of Tests 3.5 Implement the Refined Plan and Design 3.6 Execute the Test Procedures 3.7 Check for Termination 3.8 Evaluate the Test Effort and Unit

  11. Partial list of standards 610.12-1990 IEEE Standard Glossary of Software Engineering Terminology 1062, 1998 Edition IEEE Recommended Practice for Software Acquisition 1228-1994 IEEE Standard for Software Safety Plans 1233, 1998 Edition IEEE Guide for Developing System Requirements Specifications 730-1998 IEEE Standard for Software Quality Assurance Plans 828-1998 IEEE Standard for Software Configuration Management Plans

  12. Partial list of standards 1008-1987 (R1993) IEEE Standard for Software Unit Testing 1012-1998 IEEE Standard for Software Verification and Validation 1028-1997 IEEE Standard for Software Reviews 1045-1992 IEEE Standard for Software Productivity Metrics 1058-1998 IEEE Standard for Software Project Management Plans 1074-1997 IEEE Standard for Developing Software Life Cycle Processes 1219-1998 IEEE Standard for Software Maintenance

  13. Partial list of standards 1540-2001 IEEE Standard for Software Life Cycle Processes--Risk Management 1061-1998 IEEE Standard for a Software Quality Metrics Methodology 829-1998 IEEE Standard for Software Test Documentation 830-1998 IEEE Recommended Practice for Software Requirements Specifications 1016-1998 IEEE Recommended Practice for Software Design Descriptions 1044-1993 IEEE Standard Classification for Software Anomalies

  14. Classification of standards • Reference only: • Subjective • Partially Objective • Objective

  15. Classification of standards • Reference only: • declares something will happen, but there is no way to determine compliance • “Unit testing shall be carried out.” • Subjective • Partially Objective • Objective

  16. Classification of standards • Reference only: • Subjective • Only a subjective measure of conformance is possible • “Unit testing shall be carried out effectively.” • Partially Objective • Objective

  17. Classification of standards • Reference only: • Subjective • Partially Objective • A measure of conformance, but still has subjectivity • “Unit testing shall be carried • Objective

  18. Classification of standards • Reference only: • Subjective • Partially Objective • Objective • Conformance can be determined • “Unit testing shall be carried

  19. Four categories of SE Standards • Process • The Design Team shall validate the Software Specification by ... • Internal Product • e.g. code: “each module should have a single entry and exit • External Product • e.g. reliability • Resources

  20. Motivation for standards • Provide encapsulation of best practice • Avoid repetition of past mistakes • Provide framework for quality assurance (assure that standard has been followed) • Assist in continuity between workers

  21. Standards organizations • IEEE • ANSI • US DoD • NATO • Bureau of Standards

  22. How to use standards • Understand the motivation behind the development of the standard • Involve developers • Adapt standard to meet needs of organization • Review standards regularly and update to reflect changing technology • Provide software tools when possible. Clerical standards are a source of complaint

  23. “In many modern standards, the only truly mandatory activity is tailoring the standard to your particular needs.” • Lewis Gray

  24. Walkthrough of DO178B • Software Development Standard for avionics • Handbook for problem areas of software development • Catalog of certification requirements

  25. FAA Certification • The FAA certifies systems, not software • Software tools are either trusted or untrusted • The product of a trusted tool is trusted.

  26. Software Criticality Levels

  27. DO178B Process • Planning • Requirements • Design • Coding • Integral Processes

  28. DO178 Process: Planning • Languages: syntax, naming conventions, coding conventions, bounds on term complexity, indentation standards ... • Tools: which tools, which subsets, ... • Hardware: may be very stringent • Methods

  29. DO178B Planning • Describe tasks needed to meet task objectives, such as code reviews, walkthroughs, change control, audits, • Describe when processes occur, when processes exit, and who is responsible

  30. DO178B Design • How will requirements be satisfied? • Need • architecture • algorithms/data structures • I/O Description • Data and control flow descriptions • Resource strategies • Scheduling and communication

  31. DO178B Coding • Implement low-level requirements • Integration: load software onto target • Cannot patch software: need to recertify entire system (expensive)

  32. DO178B Integral Process Requirements-based test generation Low-level tests Integration tests Hardware integration tests Requirements coverage analysis Additional Verification Requirements coverage analysis

  33. DO178B Testing • MCDC: Every atomic predicate is tested • last 5% of test cases are difficult to generate • Rockwell: 30% of development budget is in structural testing

  34. DO178B Tools • Must certify for each system: previous qualification efforts don’t transfer • Qualify the tool or qualify the output? • Qualifying a verification tool is easier than qualifying a synthesis tool

  35. Evaluating Software Engineering Standards (Pfleeger, 1994) • What is a good standard? • What do the standards apply to? • What was the case study? • What did the authors find in the case study? • Teams of 2

  36. Assignment: Project teams • Find 2 IEEE standards and give 1 page summary of the standard (include references) • Find 2 “programming standards” • Summarize the standards • Compare and contrast the two standards • Develop a coding standard for your team • Due 3/24