Large-scale industrial software development

Transcription

1 Software Engineering Process Large-scale industrial software development Björn Regnell Software on Earth How many software developers? > 2 million in China > 2 million in India > 2 million in US > 2 million in EU > 10 million in the world? How much software? > 10 LOC per day per developer? > 100 million lines per day How many bugs? > 1 error per 1000 LOC? > errors per day? 1

2 Building SW from components Ever Increasing SW Complexity 2

3 From Centralized to Decentralized to Distibuted 3

4 Group Discussions Assume that you work as a software engineer with a large company. What do you think are the biggest challenges that you need to cope with? Examples of real difficulties in real industrial projects 1. What is actually the best set of requirements? 2. How much uncertainty in effort estimation can we cope with? 3. At what level of detail should we document requirements? 4. How to minimize waiting time for other parts to be ready before we can start our part? 5. How to make more parts in parallel without generating confusion and unnecessary rework? 6. How to know when the product is reliable enough to be released? 7. How to incorporate changes without generating spaghetti and excessive cost of rework? 4

5 Who are the stakeholders? External stakeholders Customers Direct customers Operators Global customers Regional customers Other key customers Retailers Indirect customers Consumers Market segments Service providers Content providers Product providers Direct Competitors Mobile phone developers Indirect Competitors Cameras Mobile music players consumer wallet competition Platform providers Operating Systems Technical Platforms Network system providers Standardization bodies Legislation and authorities National International Manufacturing sub-contractors Component providers PlayNow find the right person to talk to get the deep domain knowledge Internal stakeholders Marketing Long term branding Customer relations Product management Product planning Roadmapping and portfolios Product development Hardware design Electronics Analog Digital Mechanics Software design User interface Service logic Network access Codecs Platform development Mother, daughters, cluster Global functions Sub-contracting management Technical platforms Operating systems Original Design Manufacturing Technology forecasting Market research Customer Services Support Repair Legal Sourcing Accessories 5

6 SW Value chains are getting more and more complex... Software Ecosystems 6

7 Matrix Organization Organizing the development Pre-development in line functions; development in projects Portfolio Design Market Research Product Planning Application Planning Product Management Design Studies Product Design Technology Roadmapping Sub-domain RE Technology Outlook Technology Platform RE Standardization TIMING CHALLENGE!!! Application Platform Dev. Toll Gate Concept TG Define Hardware Dev. Software Dev. Launch Time 7

8 Orders of magnitude in Requirements Engineering Abrev. Level Order of magnitude Managing a complete set of interdependencies SSRE MSRE LSRE VLSRE Small-Scale Requirements Engineering Medium-Scale Requirements Engineering Large-Scale Requirements Engineering Very Large-Scale Requirements Engineering ~10 reqs requires small effort. ~ 100 reqs is feasible but requires large effort. ~1000 reqs is practically unfeasible, but feasible among small bundles of requirements. ~10000 reqs among small bundles of requirements is unfeasible in practice. Dealing with very large requirements databases Requirements Database Too much Profitable? Strategic? Ambiguous? Related? Group? Complete? Split? Reject? Expensive? 8

9 Complex Information Structures Market Requirements ~10000 Platform System Requirements ~10000 Features ~100 Configuration Packages ~100 Products ~100 MR1 PSR1 F1 CP1 P1 MR2 PSR2 F2 CP2 P2 MR4 MR3 PSR3 F3 CP3 P3 SR1 Cv1 Pv1 SR2 SR3 Cv2 Component Versions ~100 Supplier Requirements ~1000 Pv2 Pv3 Platform Versions ~10 MR PSR P SR Cv Pv CP F Market Requirement Platform System Req Product Supplier Requirement Component version Platform version Configuration Package Feature Challenges in Large-Scale Software Engineering Karlsson, Dahlstedt, Regnell, Natt och Dag, Persson: Requirements engineering challenges in market-driven software development - An interview study with practitioners, Information and Software Technology 49 (2007)

10 Chasm between marketing and development Engineering and marketing are not aligned Common strategy and joint future vision of RE Organisational instability and market turbulence Inability to reach steady state Stability combined with flexibility 10

11 Elementary or advanced process? To small or too large process Managed process evolution Specifications grow and grow and grow Monolithic specifications Tailored Requirements Databases 11

12 Overloaded Requirements Management Process is trashed by lack of early screening Controlled requirements selection quality and screening Resource planning Release planning Uncertain estimates of cost and value Systematic learning from estimation outcomes 12

13 Living with changing requirements Engineers want to freeze requirements Continuous and controlled allocation of requirements, readiness for controlled changes Living with design infiltration Unnecesssary restrictions imposed by low-level requirements Management of appropriate requirements abstraction level 13

14 Requirements are invented rather than discovered Blinded by technology or passively reacting on current market Balancing market pull and technology push Strategic innovation process connected to requirements engineering Requirements dependencies and bundling Dependencies are treated ad hoc Most important dependencies are managed by bundling and links 14

15 Kravberoende [Carlshamre et al., 2001] AND Ömsesidigt OCH: A kräver B och vice versa Printer kräver drivrutin och vice versa för att funka REQUIRES Ensidigt OCH: A kräver B men ej vice versa Skicka epost kräver nätverk men inte tvärtom TEMPORAL A måste implementeras före B Att lägga till bör implementeras före ta bort CVALUE A&B har annat kundvärde än var för sig on-line manual minskar värdet av tryckt manual ICOST A&B har annan kostnad än var för sig Krav på högre prestanda ökar impl. kostnaden OR Bara en av A eller B behöver implementeras Ritfunktion integrerad i ordbehandlare eller länk till annat ritverktyg Layers of Platforms Product A Rel m Product B Rel n In-house platform Application Application Platform Platform (HW+SW) (HW+SW) Release Release j j Application Platform (HW+SW) Release j Company Y Subcontracted platform Technical Technical Platform Technical Platform (HW+SW) Platform (HW+SW) Release (HW+SW) Release i Release i i Company X 15

16 Platforms as product lines => Synchronization Challenge Mobile product projects Internal system & application platform Technical platform product Internal platform (HW/SW code base) Time Milestone Requirements in sync over borders? Integrator Product Management Integration Platform Development Consumers Requriements Sub-domain working groups SRS System Req Spec for integration platform Operator Roadmaps Retailer Architecture Reguirements Detailed Reguirements SoC Statement of Compliance Hotlist Order Release Change Request Maintenance Release Device Competitor Roadmaps Requriements Sub-domain working groups Platform Competitor SRS System Req Spec for technical platform Supplier Product Management Technical Platform Development 16

17 Summary Large-scale development require processes, organizations and tools that can cope with increasing complexity Most of you will work in Large companies Small- or medium-size companies that deliver software or systems to large companies Your engineering skills depend also on How you can combine technology and economics Work in teams and with big organizations Och sedan då... Kravhantering Programvarutestning Objektorienterad modellering och design Projektplan Test Design Konfigurationshantering Ingengörsprocessen - ekonomi och kvalitet Krav Kod Binär Utvprocess Programvaruutveckling i grupp Coaching av programvaruteam Programvaruutveckling för stora system Lunds universitet / LTH / Datavetenskap / ETSA01 VT 2010 / F