SEng 5861 Introduction to Software Architecture

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SEng 5861Introduction to Software Architecture

• Week 11November 18, 2008

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Agenda

• Group exercise on contemporary topics in Software
  Architecture
• Group Discussion on exercise
• Discussion of Medvidovic Taylor paper as it
  relates to the group exercise
• Discussion of Williams Smith paper as it
  relates to rest of class guest speakers
• Discussion and clarification of group project
  phase 4 with in-class work time if time allows

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Contemporary Topics in Software Architecture

• Group exercise

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Group Exercise

• Each group gets a short paper some discussion
  suggestions.
• Groups will have 40 minutes to read through the
  paper and put together a short (10 minute)
  overview and presentation for the rest of the
  class.
• After all groups have presented and weve
  discussed individually, well have a class
  dicussion on the set of topics as a whole

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Papers for Group Exercise

• The Economics of Architecture First by Grady
  Booch (IEEE Software, Sept/Oct 2007)
• The Past, Present and Future of Software
  Architecture by Philippe Kruchten, Henk Obbink
  and Judith Stafford (IEEE Software, Mar/Apr 2006)
• The Accidental Architecture by Grady Booch
  (IEEE Software, May/June 2006)

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Papers for Group Exercise (2)

• Dealing with Change Components versus Services
  by Ahmed Elfatatry (Communications of the ACM,
  50(8))
• Sofware Architecture-Centric Methods and Agile
  Development by Robert L. Nord and James E.
  Tomayko (IEEE Software, Mar/Apr 2006)

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Discussion of papers as a wholeSome Key
Discussion Points

• What are the common themes?
• How does what we learned about architecture in
  the course play into the future of software
  architecture?

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Separating Fact from Fiction in Software
Architecture
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What is architecture good for?

• Large scale, distributed applications
• Facilitate communication
• Separation of computation from interaction
• Coarse-grained evolution
• Separation from implementation
• Style development domain specific software
  architectures

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What is software architecture not good for?

• Fine-grained evolution
• Guaranteeing the properties of the implemented
  system
• Source code optimization
• Guaranteeing the implementation of a development
  process
• Introduces another artifact to trace to/from

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Discussion Points

• Where are the architecture description languages
  that Medvidovic and Taylor talk about?
• How do the contemporary topics we discussed
  relate to whats good and not good about software
  architecture?

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Performance Evaluation of Software Architectures
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Case Study ICAD

• Computer-aided design activites
• Stores objects in a relational database
• Consists of Nodes and Elements
• Elements may be
• Beams (binary joint of two nodes)
• Triangles (connects three nodes)
• Plates (connects four or more nodes)

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Architecture 1 Class Diagram
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Architecture 1 Sequence Diagram
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Architecture 1 Process View
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Architecture 1 Physical View
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Architecture 2

• Applies the Flyweight pattern model contains
  only one instance of nodes and various types of
  elements. Used when
• of objects is large
• Cost of using objects is high
• Separate objects contain a lot of duplicated
  state

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Architecture 2 Class Diagram
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Architecture 3

• Build on Architecture 2 class diagram
• Modify DBMS to be able to retrieve a block of
  data instead of objects 1 by 1
• Reduces the number of DBMS accesses

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Architecture 3 Scenario Diagram
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Summary of Results

• Raw Performance Results
• Architecture 1 992.33s
• Architecture 2 992.27s
• Architecture 3 8s
• After simulation with Architecture 1
• Of the 992s, 990s are used for resource
  utilization
• Therefore, DBMS improvement is obvious choice
• Point These kind of techniques can locate the
  bottlenecks