Instructor: Tasneem Darwish1 University of Palestine Faculty of Applied Engineering and Urban Planning Software Engineering Department Software Systems Architecture The Architecture Business Cycle

Instructor: Tasneem Darwish2 Outlines  Introduction  Where Do Architectures Come From?  Software Processes and the Architecture Business Cycle  What Makes a "Good" Architecture?

Instructor: Tasneem Darwish3 Introduction  A software architecture is developed as the first step toward designing a system.  The software architecture of a program is the structure of the system, which include: 1.the software elements, 2.the externally visible properties of those elements, 3.the relationships among the elements.

Instructor: Tasneem Darwish4 Introduction  Software architecture is a result of technical, business, and social influence.  The Software architecture existence affects the technical, business, and social environments that subsequently influence future architectures.  We call this cycle of influences, from the environment to the architecture and back to the environment, the Architecture Business Cycle (ABC).

Instructor: Tasneem Darwish5 Where do architectures come from?  An architecture is the result of a set of business and technical decisions  We begin building the ABC by identifying the influences to and from architectures. 1.ARCHITECTURES ARE INFLUENCED BY SYSTEM STAKEHOLDERS 2.ARCHITECTURES ARE INFLUENCED BY THE DEVELOPING ORGANIZATION 3.ARCHITECTURES ARE INFLUENCED BY THE BACKGROUND AND EXPERIENCE OF THE ARCHITECTS 4.ARCHITECTURES ARE INFLUENCED BY THE TECHNICAL ENVIRONMENT

Instructor: Tasneem Darwish6 Where do architectures come from? ARCHITECTURES ARE INFLUENCED BY SYSTEM STAKEHOLDERS :  stakeholders are people and organizations interested in the construction of a software system. ( The customer, the end users, the developers, the project manager, the maintainers, and even those who market the system )  Stakeholders have different concerns that they wish the system to guarantee or optimize

Instructor: Tasneem Darwish7 Where do architectures come from? ARCHITECTURES ARE INFLUENCED BY SYSTEM STAKEHOLDERS:

Instructor: Tasneem Darwish8 Where do architectures come from? ARCHITECTURES ARE INFLUENCED BY SYSTEM STAKEHOLDERS:  each stakeholder has different concerns and goals, some of which may be contradictory.  the architect often has to fill in the blanks and mediate the conflicts.

Instructor: Tasneem Darwish9 Where do architectures come from? ARCHITECTURES ARE INFLUENCED BY THE DEVELOPING ORGANIZATION  In addition to the organizational goals expressed through requirements, an architecture is influenced by the structure or nature of the development organization  For example, if the organization has skilled programmers in client-server communications, then a client-server architecture might be the approach.  Staff skills, the development schedule and budget are all influences.

Instructor: Tasneem Darwish10 Where do architectures come from? ARCHITECTURES ARE INFLUENCED BY THE DEVELOPING ORGANIZATION  There are three classes of influence that come from the developing organization: 1.immediate business investment: using existing architectures for the new products. and the cost estimates assume a high degree of re-use. 2.long-term business investment: in an infrastructure to pursue strategic goals and the proposed system is for financing and extending that infrastructure. 3.The organizational structure: for example, the development of some of the subsystems is subcontracted because the subcontractors provided specialized expertise.

Instructor: Tasneem Darwish11 Where do architectures come from? ARCHITECTURES ARE INFLUENCED BY THE TECHNICAL ENVIRONMENT  The environment that is current when an architecture is designed will influence that architecture.  The environment might include standard industry practices or software engineering techniques common in the architect's professional community

Instructor: Tasneem Darwish12 Effects of influences on an architectures  Influences on an architecture come from a wide variety of sources. Some are only implied, while others are explicitly in conflict.  architects need to know and understand the nature, source, and priority of constraints on the project as early as possible.  Early engagement of stakeholders allows the architects to understand the constraints of the task, manage expectations and negotiate priorities.  Architecture reviews and iterative prototyping are two means for achieving it.

Instructor: Tasneem Darwish13 Effects of influences on an architectures  architects need more than just technical skills.  For an effective architect, diplomacy, negotiation, and communication skills are essential.

Instructor: Tasneem Darwish14 The Architectures effect  THE ARCHITECTURES AFFECT THE FACTORS THAT INFLUENCE THEM.  the relationships among business goals, product requirements, architects' experience, architectures, and fielded systems form a cycle with feedback loops.  A business manages this cycle to: 1. handle growth 2.to expand its enterprise area 3.to take advantage of previous investments in architecture and system building.

Instructor: Tasneem Darwish15 The Architectures effect  Some of the feedback comes from the architecture itself, and some comes from the system built from it.

Instructor: Tasneem Darwish16 How the cycle works  The architecture affects the structure of the developing organization.  The architecture can affect the goals of the developing organization  The architecture can affect customer requirements for the next system.  The process of system building will affect the architect's experience with subsequent systems  Systems will influence and change the software engineering culture and the technical environment in which system builders operate and learn

Instructor: Tasneem Darwish17 Software Processes and the ABC  Software process is the term given to the organization and management of software development activities  architecture activities have comprehensive feedback relationships with each other.

Instructor: Tasneem Darwish18 Software Processes and the ABC  What activities are involved in creating a software architecture ? 1.Creating the business case for the system 2.Understanding the requirements 3.Creating or selecting the architecture 4.Documenting and communicating the architecture 5.Analyzing or evaluating the architecture 6.Implementing the system based on the architecture 7.Ensuring that the implementation conforms to the architecture

Instructor: Tasneem Darwish19 Creating the business case for the system  Creating a business case is broader than simply assessing the market need for a system.  It is an important step in creating and constraining any future requirements.  if an architect is not consulted in the creation of the business case, it may be impossible to achieve the business goals

Instructor: Tasneem Darwish20 Creating the business case for the system  Some of the questions that a business case should answer:  How much should the product cost?  What is its targeted market?  What is its targeted time to market?  Will it need to interface with other systems?  Are there system limitations that it must work within?  These are all questions that must involve the system's architects. However, the architects cannot decide solely.