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La méthodologie MORSE F. Kordon, LIP6-SRC (UMR 7606) Université P. & M. Curie

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Présentation au sujet: "La méthodologie MORSE F. Kordon, LIP6-SRC (UMR 7606) Université P. & M. Curie"— Transcription de la présentation:

1 La méthodologie MORSE F. Kordon, LIP6-SRC (UMR 7606) Université P. & M. Curie

2 2Journée Informatique Embarquée: du matériel au logiciel - 13 Mai 2005Fabrice Kordon - UPMC Is there a future for applications out of distribution? Some examples Automatic freeway Satellite constellations Drone fleets Domotic applications Etc. Increasing complexity… …and need for reliability Main problem how to handle such applications Interactions between components (p2p approaches) Spécification, Analysis techniques, Relation to program, Deployment How to capture know-how (usability for engineers) Need for a vertical approach (no way to solve the problem locally only)

3 3Journée Informatique Embarquée: du matériel au logiciel - 13 Mai 2005Fabrice Kordon - UPMC Separation of concerns Control aspects (the difficult part;-) Computational aspects (related to an application domain) Control aspects Computational aspects Distributed Application External components Development using domain approaches Model Based Develoment Spec. of controls Formal verif. Prog. gen.

4 4Journée Informatique Embarquée: du matériel au logiciel - 13 Mai 2005Fabrice Kordon - UPMC MORSE: development Methodology centered on models Formal spec. generation Programs Program Generation UML (profile) Tests & «tuning» Reffinements Formal verif. (Petri nets, DDD) «Formal debug» LfPLfP Reformulate/ enrich LfP = pivot language

5 5Journée Informatique Embarquée: du matériel au logiciel - 13 Mai 2005Fabrice Kordon - UPMC LfP: Language overview LfP (language for prototyping) Architectural views c ensure traceability Deduced from UML + identification of communications elements Behavioral views c describe behavioral contracts Partially deduced from sequence diagrams + connection to state diagrams Property views c expected properties (guide for verification) Properties must be embedded into the specification Deployment view c for program synthesis (directives for code gen.) Link to the target architecture, detailed code generation directives Now strongly linked to a UML-profile (UML-M)

6 6Journée Informatique Embarquée: du matériel au logiciel - 13 Mai 2005Fabrice Kordon - UPMC Spec. formelle LfPLfP programes UML (profile) Focus 1: using formal methods Testing techniques fail Exhaustivity is not ensured Require formal methods «premise and problems» Need for push-button tools Approaches Theorem proving Parameterizable Difficult to automate Model checking Easy to automate Combinatorial explosion Problem, mastering the complexity

7 7Journée Informatique Embarquée: du matériel au logiciel - 13 Mai 2005Fabrice Kordon - UPMC An example, specific techniques using symbolic approaches Client code -- Get a reference to the current client task Client := Get_My_Id; -- Do the main loop loop -- computing data + server call Message := Get_This_message; Server := Get_This_server; Server.gr(client, message); -- Waiting for results accept ga; end loop Server code loop -- Waiting for an incoming service accept gr (The_Client, The_Message) do Who := The_Client; Data := The_Message; end gr; -- Processing (according to Data) if (Evaluate (Data < 2)) then Processing_1 (Data); else Processing_2 (Data); end if; -- Notifying the client Who.ga; end loop; Hypothesis: process comute only at yellow points

8 8Journée Informatique Embarquée: du matériel au logiciel - 13 Mai 2005Fabrice Kordon - UPMC Specification (Petri nets) Parameterization according to C, S et M rq ack Client c1 c2 sm ga Server s1 s2 gr1 [m < 2] gr2 [m >= 2] sa

9 9Journée Informatique Embarquée: du matériel au logiciel - 13 Mai 2005Fabrice Kordon - UPMC Where does complexity comes from? This part generates distinct but permutable values Too many concreted states (the system is symmetric, clients are permutable) Problem

10 10Journée Informatique Embarquée: du matériel au logiciel - 13 Mai 2005Fabrice Kordon - UPMC State space & Symbolic state space (C=2, S=1, M=2) A client sends M < 2 to server Two paths (C1 C2) 24 nodes, 54 arcs Same configuration, only one path (client identity can be exchanged) 14 nodes, 27 arcs

11 11Journée Informatique Embarquée: du matériel au logiciel - 13 Mai 2005Fabrice Kordon - UPMC State space does not grow anymore! Performances It is useless to have S > C ;-)

12 12Journée Informatique Embarquée: du matériel au logiciel - 13 Mai 2005Fabrice Kordon - UPMC Why this technique is applicable? Yes, Well formed Petri Nets allow such an analysis Use of structural information on the specification Identification of static subclasses All elements share the same behavior Detection of total system symmetries Extensions for partial symmetries too Is this operational? Automatic detection of static subclasses is implemented in CPN-AMI Symbolic model checking as well (cooperation with the GreatSPN kernel) Coming in the next release Larger experimentations?

13 13Journée Informatique Embarquée: du matériel au logiciel - 13 Mai 2005Fabrice Kordon - UPMC 100 millions states Almost a «hard limit» for numerous tools due to RAM size (then model checkers do swap) Other performances (PolyORB) (P4 2.4GHz 512Mo) Manual specification but same strategy 89 places, 72 transitions, 289 arcs Strongly symmetric specification

14 14Journée Informatique Embarquée: du matériel au logiciel - 13 Mai 2005Fabrice Kordon - UPMC Spec. formelle LfPLfP programes UML (profile) Focus 2: relation to programs Requires a generic prototype architecture Integrates a communication pattern with external copnents Requires a set of services (runtime) Similar to programing languages;-) Provides support functions to operate LfP specifications LfP runtime and middleware? Similar objectives Require facilities for deployment Discussed later Problem, liaison with «the world»

15 15Journée Informatique Embarquée: du matériel au logiciel - 13 Mai 2005Fabrice Kordon - UPMC From the model to the program LfP contains a deployment view Yet experimental in its syntax (XML data associated to the specification) Generation approach Partitioned view Application node Programs N1N1 N2N2 N3N3 Environment LfP Capsule (runtime) What needs for the runtime? LfP Specification LfP element (thread?) Runtime Patterns & architectures Projection of the model into implementation components

16 16Journée Informatique Embarquée: du matériel au logiciel - 13 Mai 2005Fabrice Kordon - UPMC conclusion Distributed applications are a difficult task Handling complexity of interactions Handling deployment onto machines Handling configuration (on a node) Certification, real-time, etc. Integrated methodology can help!!! Modeling and formal methods Experimentation on LfP Why not UML? goes somewhat in «the good» direction Architecture languages: Software or hardware (need both?) AADL, UML/ROOM, both? Middleware manufacturing Middleware «à la carte»

17 17Journée Informatique Embarquée: du matériel au logiciel - 13 Mai 2005Fabrice Kordon - UPMC Advertising;-) the MORSE project Méthodes et Outils pour la Réalisation et la vérification formelle de Systèmes interopérables Embarqués critiques RNTL project (June June 2006) Sagem SA (project leader) Aonix LIP6-SRC LaBRI Objectives: a methodology with its (prototype;-) tools Prototyping approach Use of formal methods for verifying the system Use of a pivot language Integration of legacy code

18 18Journée Informatique Embarquée: du matériel au logiciel - 13 Mai 2005Fabrice Kordon - UPMC Many perspectives Need for dynamic adaptation (at execution time) Some techniques are available Virtual Virtual machines (for the runtime)… Need to control the development of transformation tools Model engineering techniques are available Metamodeling techniques? Transformation languages? Need for more formal techniques Management of time? Probabilistic analysis? Etc… There is still some interesting work to come;-)


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