Contributions to the safe execution of dynamic component-based real-time systems

• Autores: Julio Ángel Cano Romero
• Directores de la Tesis: María de la Soledad García Valls (dir. tes.)
• Lectura: En la Universidad Carlos III de Madrid ( España ) en 2013
• Idioma: inglés
• Tribunal Calificador de la Tesis: Juan Antonio de la Puente Alfaro (presid.), Carlos Delgado Kloos (secret.), Giuseppe Lipari (voc.)
• Materias:
  • Matemáticas
    • Ciencia de los ordenadores
      • Sistemas de información, diseño y componentes
  • Ciencias tecnológicas
    • Tecnología de los ordenadores
      • Sistemas en tiempo real
• Enlaces
  • Tesis en acceso abierto en: e-Archivo
• Resumen

  • Traditionally, real-time systems have based their design and execution on barely dynamic models to ensure, since design time, the temporal guarantees in the execution of their functionality. Great effort is being applied nowadays to progressively develop more dynamic systems, with the target of changing during their execution and to adapt themselves to their environment. The capability to change and to reconfigure themselves represents remarkable advantages as the capability to fix errors and to add new functionality with on-line updates. This means to be able to be updated without needing to stop the service, that may imply monetary losses in many cases. Design and development techniques based on components have become popular due to the use of components, which allows simplifying the system design, code reusability and updates through the substitution of components. The target of this thesis work is to provide certain degree of dynamism to real-time systems allowing them to replace components, incorporating new functionality of fixing existing bugs. On that purpose, a component-based framework is proposed, as well as the corresponding task in charge of providing dynamism to the system. The main contribution is to provide a framework to allow safe component replacements. Safe meaning that incorrect executions of tasks are avoided even y multiple tasks are executing concurrently and making use of the same data. Also that temporal guarantees are provided for every task. This framework incorporates a generic component model with real-time threads, a components replacement model with execution times that are known and bounded, and different strategies to apply such component replacement model. Some mechanisms to maintain a seamless and safe execution, regarding concurrency, before, during, and after applying the processes in charge of replacing running components are also described. Seamless execution means that components themselves do not perform the replacements, and safe means that temporal guarantees are provided and components are not affected in their execution. Part of these mechanisms are the system schedulability analysis and the framework tasks as well as reserving the needed resources for such scheduling to be correct. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------