6. Architectures Flashcards
Why is there a need for architecture?
There is a need to describe the structure of information systems, just as you must describe the designing and building of a house. An easy description/overview of tech and processes that helps you make strategic decisions –> that IT can respond easier to.
What is an ‘architecture’ according to TOGAF?
Architecture description is a formal description of an information system that supports reasoning about the structural properties of the system. It defines components or building blocks that it is made of, and provides a plan from which product can be produced and systems developed, that will work together to implement the overall system. –> in this way it helps you manage your overall IT investment so that it meets your business needs.
How is IS planning similar to urban planning?
Because it is a map of different subsystems and components and how everything fits together to enable the flow that we want. It is super complex in this way. All areas have their own set of rules and then all have connections (shared systems, linkages) to each other and these linkages also have their own rules etc. –> so describing the architecture is important, because if you change one component, you need to know how everything else is affected.
Enterprise architecture is…
The highest level of description of an organization and typically covers all missions and functions. Can often span over multiple organizations.
The balance between synergy and independece:
Trade-off. You may want to split off some parts (ex outsourcing) or isolate parts to put into standard software, but if you have an integrated model - adding or splitting will come at a high price. Sometimes it’s better to have some redundancy/less integrated to make it easier to add/split, itäs about agility.
Advantages of having good technical architecture:
- Lower cost during all phases (develop, support, maintenance)
- Increased portability of applications
- Improved interoperability
- Reduced complexity in IT infrastructure
- Higher sourcing flexibility
- Simpler procurement decisions.
+ and - with Universal modelling language (UML):
+ large set of descriptions
+ one language for all levels
+ well defined
+well established
- too precise?
- intuitive overview?
- does business understand UML?
Three architectures:
- Business architecture.
- Information systems architecture (data + application arch)
- Technology architecture
How can the three levels influence each other?
At the top is the business arch and it influences the IS architecture, which in turn influences the lowest level of tech arch. It cannot influence from bottom-up.
Business architecture:
Defines business strategy, governance, organization and key processes = link to business. Very much related to business processes and core entities.
How to model business architecture?
Can use Business Process Modelling Notation (BPMN)
Information system architecture:
Data + Application:
- Data describes the structure of an org’s logical and physical data asset and data mngmt resources.
Data models + object models.
- Applic arch provides a blueprint for the ind. applications to be deployed, their interactions and relationships to core business processes. The ‘big picture’ and view of all components.
Technology architecture:
Describes the logical software and hardware capabilities required to support the deployment of business, data and application services, this incl it infrastructure, middleware, networks, applications = link to software and programming and integrators. It’s a plan for implementing the application architecture.
What is ‘middleware’?
Middleware speeds development of distributed applications by simplifying connectivity between applications, application components and back-end data sources. Middleware is software that enables one or more kinds of communication or connectivity between two or more applications or application components in a distributed network.
3 most popular methods for Enterprise architecture:
- Zachmann - 5 levels which each look into 6 dimensions. Very detailed and not easy for business to understand.
- IBM - an iterative approach.
- TOGAF - a development cycle
