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Linux as a Case Study: Its Extracted Software Architecture
Paper By: Ivan T. Bowman, Richard C. Holt and Neil V. Brewster Slides By: Jack ZhenMing Jiang
CISC 322 Software/Game Architecture Module 4: Examples of - - PowerPoint PPT Presentation
CISC 322 Software/Game Architecture Module 4: Examples of - - PowerPoint PPT Presentation
CISC 322 Software/Game Architecture Module 4: Examples of Architectures (Linux) Ahmed E. Hassan Linux as a Case Study: Its Extracted Software Architecture Paper By: Ivan T. Bowman, Richard C. Holt and Neil V. Brewster Slides By: Jack
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Outline
l Terminology l Conceptual Architecture l Concrete Architecture l Conclusions
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Terminology
l Conceptual Architecture
– How developers think of a system; Relations meaningful to
developers
– Analogy: Blue Print of the House – By Reviewing Existing Documentation – Essential Relations
l Concrete Architecture
– Relations that exists in a system – Analogy: Actual Architecture of the House – By Examining the Source Code – Implementation Specific Knowledge
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The Linux Kernel
l Responsible for process, memory, and
hardware device management
– Different from the Linux System
l Linux System: 10 KLOC in 1991 to 1.5
MLOC in 1998
l The studied Linux Kernel is 800 KLOC l Open Source
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Conceptual Architecture – Top Level
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Conceptual Architecture – File System
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Façade Pattern Object Oriented Style 1
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Concrete Architecture – Extraction Methodology
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Control Flow Data Flow Manually
- Group Directory to Subsystems
- Naming Conventions
Feedback
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Concrete Architecture – Top Level
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Concrete Architecture – File System
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Concrete Architecture – File System
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Concrete Architecture – Logical File System
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Why Conceptual Architecture and Concrete Architecture Not Match?
l Missing Relations in Conceptual Architecture l More Functionalities
– For example, Process Scheduler
l Use Different Mechanisms l Improve Efficiency by Bypassing Existing
Interfaces
l Exist for Developer Expediency
– “The read-only stuff doesn’t really belong here, but
any other place is probably as bad and I don’t want to create yet another include file.”
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What To Do Next?
l Restructure to Remove Unexpected
Dependencies
– Header Files – Lower Coupling
l Refine Conceptual Architecture
– Not Hinder System Understanding
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Conclusions
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l Conceptual and Concrete Architecture
for the Linux Kernel
l Similar Work Needs to Be Done for the
Firefox Report
l Sample Reports:
– Conceptual Architecture:
http://plg.uwaterloo.ca/~itbowman/CS746G/ a1/
– Concrete Architecture:
http://plg.uwaterloo.ca/~itbowman/CS746G/ a2/