LHCb Computing Organisation and Development Strategy Presented to ATLAS Architecture WG July 16th, 1999 J.Harvey / LHCb

LHCb organisation and devlopment strategy Slide 2 Getting Basic Infrastructure Right qNeed to focus on quality but at the same time be efficient in use of resources qIdentify all the roles and their responsibilities e.g. : ãsystem architect, project leaders, librarian, framework developers (engineers), client developers (physicists),... ãpackage interdependencies require approval of system architect qGood communication to arrive at common aims and understanding ãneed to know at all times what everyone is doing - regular contact ãProcedures for taking decisions must be agreed and followed qCommon language supported through documentation and training ãUser Handbook - what every collaborator needs to know ãEngineering Handbook - what every software engineer needs to know ãManagement Handbook - guidelines for creating and running a software project (project management, configuration management,…) qDevelopment Process and Organisation must support the above goals

LHCb organisation and devlopment strategy Slide 3 Process for Organising Software Development Activities Manage Plan, initiate, track, coordinate Set priorities and schedules, resolve conflicts Support Support development processes Manage and maintain components Certify, classify, distribute Document, give feedback Assemble Design application Find and specialise components Develop missing components Integrate components Requirements Existing software systems Build Develop models, Evaluate toolkits Architect components and systems Choose integration standard Engineer reusable components

Support Facilities CPU farms Desktop Storage Network System Man. Vendors IT-IPT.. Vendors IT-PDP Vendors, IT-ASD Support Software SDE Process Quality Librarian Training Webmaster MM Build Frameworks Architecture, Components, Integration technology, Libraries and toolkits A Reconstruction M Simulation M Analysis M Controls M Control Room M Assemble DAQ M Manage Steering Group MM C Technical Review EM A... Arch. Review MA E... M A C E Coordinator Architect Project Manager Project Engineer LHCb Computing Project Organisation

LHCb organisation and devlopment strategy Slide 5 Strategy for development of new software qWe are convinced of the importance of the architecture qFirst crucial step is to appoint an architect - ideally should have skills as: ãsoftware engineer - designer and technologist (OO mentor) ãphysicist - knowledge of data processing applications, how they are used ãmanager - form, lead and inspire the design team ãvisionary - have clear picture of what architecture should look like in practice qStart with small design team 6-8 people ãneed domain specialists experienced in design/programming ãneed librarian qControl activities through visibility and self discipline ãmeet regularly - in the beginning every day, now twice per week qCollect URs and scenarios, use to validate the design qEstablish the basic design criteria for the overall architecture ãarchitectural style, flow of control, specification of interfaces qMake technology choices for implementations of first prototypes ãlanguage, code repository, design tool, ….

LHCb organisation and devlopment strategy Slide 6 Strategy for development of new software qIdentify components, define their interfaces, relationships among them qBuild frameworks from implementations of these components ã“framework is an artefact that guarantees the architecture is respected” ãA framework provides architectural guidance by partitioning the design into abstract classes and defining their responsibilities and collaborations ãA client developer customizes the framework to a particular application by subclassing and composing instances of framework classes ãExamples are the GUI, event data management, histogramming, …. ãEach framework built by small team of specialists (2-4 people) ãEach framework corresponds to 1 or more deliverable packages qFrameworks to be used in all the LHCb event data processing applications: ãhigh level trigger, full reconstruction,.. ãsimulation, physics analysis,.. ãevent display, data quality monitoring, bookkeeping,.. ãrun control, detector control and monitoring,..

LHCb organisation and devlopment strategy Slide 7 Strategy for development of new software qIncremental approach to development ãnew release every few (~ 4) months ãsoftware workshop timed to coincide with new release qDevelopment cycle is user-driven ãUsers define priority of what goes in the next release ãIdeally they use what is produced and give rapid feedback ãFrameworks must do a lot and be easy to use qStrategic decisions taken following thorough review (~1 /year) qReleases accompanied by complete documentation ãpresentations, tutorials ãURD, reference documents, user guides, examples

LHCb organisation and devlopment strategy Slide 8 Schedule so far qSept 98 - architect appointed, design team of 6 people assembled qNov 25 ’ day architecture review ãgoals, architecture design document, URD, scenarios ãchair, recorder, architect, external reviewers qFeb 8 ’99 - GAUDI first release ãfirst software week with presentations and tutorial sessions ãplan for second release ãexpand GAUDI team to cover new domains (e.g. analysis toolkits, visualisation) qMay 30 ‘99 - GAUDI second release ãsecond software week… ãplan for third release ãexpand GAUDI team to cover new domains (GEANT4 simulation toolkit) qNov ‘ 99 - next GAUDI release and software week planned

LHCb organisation and devlopment strategy Slide 9 LHCb Offline Software Road Map Working Prototype, ‘retire’ SICB Detailed Implementation Integration and CommissioningExploitation Release Number 2006 Incremental releases Review Major Technology Choices