Reliable Architecture Ved Henrik Bærbak Christensen Reflective Architectures Emne: reflective architecture overview 11 december 2009

Seminar Notes Reflective architecture Generelt reflection: Arkitekturen har forståelse for sig selv Garlan: Adaptor laget til systemet skal bare ændres, hvis den samme style anvendes Gjerluf: Nævner ikke styles, fordi H-graps er en design style i sig selv herunder programmeringsmodel. Denne kan måske ikke anvendes til alle problemdomæner

Opgave Beskrivelse 1.The Garlan et al. paper describes a way to increase dependability by architectural means. Outline the requirements on the system in order for their proposal to work. 2.Outline the elements of their Architectural Model and how they define Architectural Style. 3.Fig 1. is a rich picture outlining their adaptation framework. Express instaed using a component-connector view as well as a deployment view as defined by Christensen et al. 4.Explain what Adapation Operators and Repair Strategies are and how they can be used to adapt the architecture. Why are they linked to architectural style? 5.Describe the monitoring/gauge system. How could such a system be implemented? 6.Relate the approach of Garlan et al. to 1.Autonomic computing: what aspects of self-* are their approach addressing? 2.Sommerville's definition of dependeability. What aspects is in focus? Could other aspects also be addressed by their approach? 7.Discuss whether their approach is feasible even without the use of their research tools, like Acme, Armani, etc. 8.Gjerlufsen et al. describe a radical different approach to architectural reflection. Describe the central ideas of the approach, and how they support architectural reflection. 9.Contrast and discuss Figure 1. of Gjerlufsen with the approach outlined by Garlan. 10.Outline the set design objectives for the H-map programming model, as well as what the software design "should do". 11.Garlan et al. discuss in terms of Architectural Style. How does Gjerlufsen et al. never discuss the concept of a style? 12.Discuss how the H-map approach may support "reliable architectures". Use the concepts of Sommerville, Luy, and others to discuss the approach's applicability. 13.Contrast and discuss the H-map approach to autonomic computing. 14.Contrast both approaches to the concepts of virtualization and debugging.

Gruppe præsentation på seminar Introduktion: -Forbedre system pålidelighed -Selv reparende systemer afgøre hvornår en handling er påkrævet i form af en adaptation -Self reparende systemer tidligere expection eller RPC timout baseret og triggere -Ulemper: har svært ved at fange reduction af performance, tranisiente fejl -Ny tilgang : arkitektur modeller -Global perspektiv af system til identifikation af problemer -Arkitektur style som en runtime entitet der monitorer systemet og detekterer afviglser -Arkitektur er koblet med system kontruktion -Runtime model af systemet -Basis for system reparation

Arkitektur style – Komponent typer og deres relationer og constraints Arkitektur adaption framework steps 1.Eksekverings system 2.Monitorings mekanisker – runtime opførsel 3.Arkitektur model 4.Analyser 5.Reparations handler (adpat arkitektur) 6.Arkitektur til system translator til runtime handler

style Hvilke properties overvåges Constraints Hvad der sker når constraints brydes Hvordan sker reparation

Arkitektur stype (filter s.68) Typer, komponenter, interfaces, connectors og properties Graf Hvis man overholder style supporteres: analyse, genbrug, kodegeneration og evolution

1. Monitorering Gauges er model specifikke Konvertere fra low level observations til properties og mere abstrakte repræsentationer

2. Repair