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Seminar Fehlertoleranz und Echtzeit für E-Commerce Prof. Miroslaw Malek Peter K. Ibach

Seminar Fehlertoleranz und Echtzeit für E-Commerce Prof. Miroslaw Malek Peter K. Ibach. e-l ab. Terminplan. Terminplan. Dependability Tree (Laprie 95). Combined Fault Classes (Laprie 95). Failure Classification (Laprie 95). Fault Model (Christian 1991).

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Seminar Fehlertoleranz und Echtzeit für E-Commerce Prof. Miroslaw Malek Peter K. Ibach

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  1. SeminarFehlertoleranz und Echtzeitfür E-CommerceProf. Miroslaw MalekPeter K. Ibach e-lab

  2. Terminplan

  3. Terminplan

  4. Dependability Tree (Laprie 95)

  5. Combined Fault Classes (Laprie 95)

  6. Failure Classification (Laprie 95)

  7. Fault Model (Christian 1991) • Timing Fault (TF): the task completes after the deadline specified or never (ei > ci) • Crash Fault (CF): a server omits to respond to all subsequent input until it restarts • Fail Stop (FS): a server informs the system in case of a crash fault • Value fault: the output is incorrect (not subject to be tolerated) Suitable model if: • a server can exceed the specified task worst-case execution time, or • the network can delay messages, but • it is unlikely that computation results or messages are corrupted.

  8. Timing error The task completes after the deadline specified or never (ei > ci). Special cases of the (arbitrary) timing error are the early timingerror, the late timing error, and the infinitely late timing error. Software fault: programming faults in the code of a task instance that produce infinite loops or other execution delay. Specification fault: bad (under-estimated) evaluation of WCET ci. Crash fault: A server omits to respond to all subsequent input until it restarts Fail ftop: A server informs the system in case of a crash fault Value error The task completes with an incorrect result. Impromptu error The system spontaneously delivers a service item that was not specified. Error Classes

  9. Fault Tolerance Techniques • Error detection • Error diagnosis • Error recovery • Backward recovery • Forward recovery • Compensation • Hardware Fault Tolerance • Software Fault Tolerance

  10. Echtzeit-Systeme DSPecialist.ppt

  11. Echtzeit-Systeme RTsystems.ppt

  12. Vorhersage von Antwortzeiten Predictor.ppt

  13. IBM "Autumn School" • vom 2.10. bis 6.10.2000 • "Autumn School" zum Themenkreis e-Business • Ort: Berlin • Praktiker von IBM stellen Vorgehensweisen im Bereich Projektmanagement vor • Lösungsarchitekturen werden diskutiert • Hands-On Erfahrungen • eingeladen: Hauptstudiums-/Promotions- Studenten mit e-Business Qualifikation

  14. Scheduling for Responsiveness How should real-time tasks be allocated to nodes and in what order should they be executed?

  15. Responsiveness Reliability (system specific) R(t) = P(no system failure until time t) Responsiveness (specific to load and fault assumptions) r(t) = P(no task failure** until time t)

  16. Task fault probability of task i Responsiveness without replication Responsiveness with duplication Responsiveness

  17. Themen (1) • Hardware • Ausfallsichere Linux Cluster • Shared Disk Systeme - Zugriff auf gemeinsame Festplatten • Redundanter Netzzugang - Betrieb mehrerer Netzwerkanschlüsse • Unterbrechungsfreie Stromversorgung

  18. Themen (2) • Middleware • Clustering/Lastballancierung - Middleware Lösungen für Commodity (Massenware) Cluster • Echtzeit – Lastanalysen, Bearbeitung der Anfragen nach Prioritäten bzw. Zeitschranken, Überlastsicherung, Zeitvorhersagen • Verteilte Datenbanken - Was ist in E-Commerce Transaktionssystemen zu beachten? • Mobile Endgeräte - Wie kann man Handys (WAP, SMS) und andere Endgeräte integrieren?

  19. Themen (3) • E-Commerce Anwendungen • Shop Lösungen - Intershop und Co. Überblick über die Features der verbreiteten Shopsysteme • ePayment systeme - Wie kann man bezahlen? • Auktionssysteme • Satellitenkomponenten - Personalisierung, B2B, Navigation/Retrieval, etc?

  20. Themen (4) • Beispielszenarien / Content • Virtual Office – Daten sind von überall aus über beliebige Endgeräte zugreifbar • Elektronische Second-Hand Börse – Vermittlung von gebrauchten Gegenständen • Börsensystem • Game/Entertainment – Videoserver, Netzwerkspiele, Majority Voting Chess • Allgemeine Shoplösung Integration von Prewiev, Photos, Warenkorb, Bezahlfunktion, Bestellauslösung

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