Page 83 - DCAP305_PRINCIPLES_OF_SOFTWARE_ENGINEERING

Unit 4: Introduction to Validation, Metrics

structural choices out, and guides selection decisions and trade-offs among others. By choosing Notes
message or co-ordination mechanisms that are repeatedly applied across the architecture, a
consistent approach is ensured and this simplifies the architecture. It is also very useful at this
stage, to find a metaphor or organizing concept that works for your system. It will help you
think about the qualities that the system should have, it may even help you think about what
components you need (in Conceptual Architecture), and it will certainly help you make the
architecture more vivid and understandable.

Figure 4.10: Architecture Views

4.2.2 Conceptual Architecture
The Conceptual Architecture identifies the sophisticated mechanism of the system, and the
relations among them. Its purpose is to direct concentration at a suitable decomposition of the
system without delving into details. Moreover, it provides a useful vehicle for communicating the
architecture to non-technical audiences, such as management, marketing, and users. It consists
of the Architecture Diagram (without interface detail) and an informal component specification
for each component.

4.2.3 Logical Architecture
In rational Architecture, the externally visible properties of the components are made precise and
unambiguous through well-defined interfaces and component specifications, and key architectural
mechanisms are detailed. The rational structural design provides a detailed “blueprint” from
which component developers and component users can work in relative independence. It
incorporates the detailed structural design Diagram (with interfaces), Component and Interface
Specifications, and Component Collaboration Diagrams, along with discussion and explanations
of mechanisms, rationale, etc.

4.2.4 Execution Architecture
An Execution Architecture is created for distributed or simultaneous systems. The process view
shows the mapping of components onto the processes of the physical system, with attention
being focused on such concerns as throughput and scalability. The deployment view shows the
mapping of (physical) components in the executing system onto the nodes of the physical system.
Software architecture consists of:

1. Elements: Processing elements (“functions”), connectors (“glue” procedure calls, messages,
events, shared storage cells), data elements (what “flows” between the processing elements).

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