Introduction to Business Process Engineering?

System engineering helps to translate the needs of the customer into a system model that makes use of elements like software, hardware, people, database, documentation and procedures.
Business process engineering is a system engineering approach that defines architecture enabling a business to use the information more effectively and efficiently. It helps in creating an overall plan for implementing computing architecture.

There are three different types of architectures defined and developed keeping business goals in mind. These are:

- Data architectures provides a framework. Data objects used by business are building blocks. After defining the data objects, the relationships among them are identified. The data objects flow between business functions are organized within database and are transformed to provide information.
- Application architectures is a system of programs that transforms objects within data architecture for business purpose.
- Technology architecture provides the foundation for data and application architecture. It includes hardware and software used to support data and application.

The main aim of business process engineering is to derive data architecture, application architecture and technology infrastructure which will meet the needs, goals and objectives of the business.

What is Software Architecture ? What are subsystems and interfaces?

Software architecture defines a set of decisions about the organization. It includes:
- how to select structural elements.
- how to select their interfaces.
- how to select the behavior.
- how to select the composition of these structural and behavioral elements into larger subsystems.
- architectural style that guides this organization.
A software architecture is a description of the sub-systems and components of a software system and the relationships between them.
Software architecture is layered structure of software components and the manner in which these components interact.
A software architecture is modeled using package diagram of UML. A package is a model element that can contain other elements.
A subsystem is a combination of package and class. The advantages of defining subsystem are:
- Development of smaller units is possible.
- Re-usability increases.
- Handling complexity is managed properly.
- Maintainability eases.
- Supports portability.

An interface is a set of operations.
- Allows the separation of the declaration of behavior from the realization of the behavior.
- Serves as a contract to help in the independent development of the components by the development team, and ensures that the components can work together.
- There are two styles of communication subsystems use: client-server and peer-to-peer communication.