1. Project Management effects on software dependability Brendan Murphy Microsoft Research Cambridge, UK

2. E-Science Dec 2002. Agenda Developing solutions. Developing solutions. Exploring ‘dependability’ Exploring ‘dependability’ Ignored areas of dependability. Ignored areas of dependability. Program Management of Windows NT (brief overview). Program Management of Windows NT (brief overview).

3. E-Science Dec 2002. Achieving highly dependable software programs. Business Man Problem Software Architect Solution Software Engineers Software Users

4. E-Science Dec 2002. What went wrong Business Man Software Architect Software Engineers Software Users Problem Reduce costs De-skill Problem definition Understand concepts Exceptions? Knowledge of solution? Clear Responsibilities Ownership? Different Environments! Not tested in Production environment. System Manager de-motivated.

5. E-Science Dec 2002. Apply other engineering disciplines to software (e.g. trains)! Original problem. People had there own trains. People had there own trains. Many different track designs. Many different track designs. Variations in train design. Variations in train design. Solution - redefined the problem Standardization. Standardization. People training. People training. 150+ year of trial and error. 150+ year of trial and error. Result a dependable but inflexible process. Red for danger L.C.Rolt

6. E-Science Dec 2002. Developing dependable systems. Solution. Develop specialized hardware. Develop specialized hardware. Write your own OS and applications. Write your own OS and applications. Employ highly trained users and operators. Employ highly trained users and operators.Problems Very expensive. Very expensive. Difficult to get staff. Difficult to get staff. Comparison to commercial products. Comparison to commercial products.

7. E-Science Dec 2002. Dependability requirements bugs/KLOC? Problem. Dependability needs. Safety Critical Predictability. Business Process. Knowledge transfer. Database development. Data integrity. New product. Very little.

8. E-Science Dec 2002. Overlooked dependability issues System Recovery of OpenVMS systems. System Reliability Issues, FTC 1999 Murphy, Davies Single events can Induce periods of System instability.

9. E-Science Dec 2002. Knowledge affects dependability. OpenVMS dependability improvement over time. Operating System behaviour improves with age? Few new patches are produced 6 months after the release of any version of the Operating System. System Reliability Issues, FTC 1999 Murphy, Davies

10. E-Science Dec 2002. Project Management at Microsoft. Ideal A standard predictable process producing dependable and secure software. A standard predictable process producing dependable and secure software.Reality No ideal process exists. No ideal process exists. Development teams have flexibility in their development process. Development teams have flexibility in their development process. System test and release a separate process. System test and release a separate process. Continuous tool development. Continuous tool development. User Interface a separate group. User Interface a separate group.

11. E-Science Dec 2002. Windows NT development. Development Teams (e.g. kernel) Responsible for Design Implement Testing Release Management System Test Development System Verification Software Legacy computer New hardware and drivers Legacy applications New applications

12. E-Science Dec 2002. NT Development

13. E-Science Dec 2002. Summary Understand product dependability from the end user perspective. Understand product dependability from the end user perspective. Assume you will not reach perfection. Assume you will not reach perfection. Understand the preferences/dislikes of the development team. Understand the preferences/dislikes of the development team. Then choose the development and program management process. Then choose the development and program management process.