1. Princess Nourah bint Abdulrahman University
Architectural Design
Princess Nourah bint Abdulrahman University
College of Computer and Information Sciences Department of Computer Science
Dr. Doaa Sami Khafaga

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Software Engineering
Architectural Design

3. Topics covered Introduction Architectural design decisions
System organisation
Decomposition models
Control models
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6. UML diagram of system parts
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Architectural Design

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Architectural Design

9. Topics covered Introduction Architectural design decisions
System organisation
Decomposition models
Control models
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Software Engineering
Architectural Design

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Software Engineering
Architectural Design

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13. Architectural design process: System structuring
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20. Example: Architectural design for “Packing robot control system”
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21. Topics covered Introduction Architectural design decisions
System organisation
Decomposition models
Control models
S.H
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Software Engineering
Architectural Design

22. System Organisation
Reflects the basic strategy that is used to structure the system
Three architectural styles are widely used:
Shared data repository
Client-server (services and servers)
Abstract machine or layered style
S.H
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Software Engineering
Architectural Design

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24. Example: repository model for “CASE toolset architecture”
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25. Repository Model Characteristics
Advantages
Can efficiently share large amounts of data
Sub-systems need not be concerned with how data is produced by other sub-systems
Centralized backup, access control, and error recovery
New tools compatible with the repository schema (data model) are easily integrated
Disadvantages
Sub-systems must agree on a repository data model, compromising on needs of each tool, affecting performance and integration with incompatible tools
Translating data into different data model is difficult, expensive, or impossible;
Same policy forced on all sub-systems
Difficult to distribute repository over many machines efficiently, leading to problems with data redundancy and inconsistency
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27. Example: Client-server architecture for Film and picture library
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29. (Layered Model) Difficult to structure system in layers:
Inner layers may provide services required in several layers, making outer layers depend on more than its adjacent layer
Performance may suffer when service requests must be interpreted across
many layers before processing
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30. Example: Abstract machine model for Version management system
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31. Topics covered Introduction Architectural design decisions
System organisation
Decomposition models
Control models
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Architectural Design

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33. Object models decomposition
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34. Example: Object models for Invoice processing system
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35. Object models decomposition
Advantages:
Loose coupling ensures that changes in one object class does not affect other objects
Since objects tend to reflect real-world entities, object models are easy to understand
Disadvantages:
Changes to the interface of an object have an impact on other users of the object
Complex entities may be difficult to represent as objects
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Software Engineering
Architectural Design

36. Function-Oriented Pipelining
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37. Example: Data-flow models for Invoice processing system
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38. Function-Oriented Pipelining
Advantages:
Supports reuse of transformations
Intuitive for many who view work as input, processing, and output
Easy to evolve system by adding new transformations
Simple to implement as concurrent or sequential system
Disadvantages:
Requires common data format for all transformations
Event-driven interactions are hard to support
S.H
230810
Software Engineering
Architectural Design

39. Topics covered Introduction Architectural design decisions
System organisation
Decomposition models
Control models
S.H
230910
Software Engineering
Architectural Design

40. Control models
Refers to the control flow between sub-systems (not the same as system decomposition model)
Centralized control
One sub-system has overall responsibility for control and to start/shutdown other sub-systems
Event-based control
Each sub-system can respond to externally generated events; these events may come from other sub-systems or the system environment
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42. Centralised control
One sub-system is responsible for managing the execution of other sub-systems.
Depending on whether the controlled sub-system executes sequentially or in parallel, the centralized control models may be:
Call-return model: Applicable to sequential systems. Control starts at the top of the hierarchy, and passes to lower level processes via function calls
Manager model: Applicable to concurrent systems. Controlled by a designated manager system component that coordinates other processes
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43. Centralized control: Call-return control
model
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45. Centralized control: Manager control model
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46. Example: Manager control model for Real-time system control
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48. Event-driven systems: Broadcast model
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49. Event-driven systems: Selective broadcasting
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50. Event-driven systems: Interrupt-driven systems
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51. Event-driven systems: Interrupt-driven control
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