Introdução à Arquitetura de Software

Editor's Notes

• #2: Vitruvius = Marco VitruviusA arquitetura se manifesta de dois modos diferentes: a atividade (a arte, o campo de trabalho do arquiteto) e o resultado físico (o conjunto construído de um arquiteto, de um povo e da humanidade como um todo).Arquitetura, no seu sentido primeiro e mais amplo, refere-se, em uma acepção tradicional, à arte e técnica de organizar e configurar espaços a fim de construir o meio-ambiente propício à vida humana. Arquitetura é música petrificada,Johann Wolfgang von Goethe
• #3: Arquitetura Cultural é uma metodologia de planejamento e construção de empreendimentos e políticas privadas sustentáveis, que gerem impacto sociocultural positivo, alicerçados na visão estratégica, no valor sócio-econômico do negócio e no compromisso ético da empresa com a sociedade e com o desenvolvimento humano.A arquitetura cenográfica (cênica) ocupa-se mais especificamente da geração dos cenários arquitetônicos internos ou externos.A arquitetura de computadores é a teoria por detrás do desenho de um computador.A Arquitetura de Informações consiste no design de ambientes informacionais compartilhados e resistentes à entropia, que vem a ser o estado de desordem natural de qualquer sistema, na ausência de uma força organizadora.Arquitetura de rede é como se designa um conjunto de camadas e protocolos de rede
• #4: Pioneiros
• #5: Distinguish the development of software systems from the development of physical systems. With software, time matters. Software is all about state and changing state. There are usually a large number of states the software can exist in, and the software behavior may be very complex, which makes it difficult to analyze all of the different state combinations. This is different than with physical systems where even moving elements have a finite number of states.Physical systems are constrained and governed by the laws of physics. On the other hand, with software systems, you can do anything you want. This makes visible and physical systems easier to architect.Many physical systems such as buildings, are static structures. Software systems have both static and dynamic perspectives.Software is assumed to evolve and hence it is built in such a way that applying changes should be inexpensive. Adaptability is the rule for software. In fact, adaptability is the very nature of expert systems. Physical systems are not really built to change over time. Per physical systems engineering standards, software systems are perpetually in the design and prototyping stage. At some point, a running version is good enough to be released. Since the replication and distribution costs are very low (e.g., just burn a CD), new releases can be produced very frequently (we are not saying that this is desirable). In other words, software development is a continuous design process, where the manufacturing cost is effectively zero. This is unlike hardware systems where you build once and spend the rest of the time manufacturing.Software architecting is less predictable and more risk-building that hardware architecting. Thus, software is becoming more complex and difficult to build than hardware.
• #6: Architecture is many things to many different stakeholdersEnd userCustomerSys adminProject managerSystem engineerDeveloperArchitectMaintainerTesterOther systemsArchitecture defines major componentsArchitecture defines component relationships (structures) and interactionsArchitecture omits content information about components that does not pertain to their interactions Behavior of components is a part of architecture insofar as it can be discerned from the point of view of another componentEvery system has an architecture (even a system composed of one component)Architecture defines the rationale behind the components and the structureArchitecture definitions do not define what a component isArchitecture is not a single structure -- no single structure is the architecture
• #7: Functional/logic viewCode/module viewDevelopment/structural viewConcurrency/process/thread viewPhysical/deployment viewUser action/feedback viewData view
• #8: A system’s architecture ultimately resides in executable codeA system’s architecture may be visualized in modelsEvery system has an architecture; some architectures are made manifest and visible, many others are notAll architecture is design, but not all design is architectureInfrastructure is an integral and important part of architecture, but there is more to architecture than just infrastructureA given technology only serves to implement some dimension of an architectureTechnology shapes an architecture, but a resilient architecture should never be bound to all of the technologies that form itConceptual integrity is essential, but the complexity of most interesting systems leads development to be a team sportMultiple stakeholders with multiple concerns lead to multiple views with multiple blueprintsThere exists only a modest body of knowledge about software architectureScientific and analytical methods are lacking; those that do exist are hard to applyThere is no perfect design; architecture involves the management of extreme ambiguity and contradictionExperience counts: the best architects are grown, not bornEven the best architects copy solutionsThe “artsy” part of software architecture is minimal
• #9: FunctionalityUsabilityPerformanceScalabilityChangeabilityComprehensibility / Habitability (Patterns of Software)EcosystemModularityReusabilitySecurityReliability