Overall Evaluation of Software Architecture

1
Overall Evaluation of Software Architecture

• By
• Ashwin Somaiah

2
The ATAM A Method

• The name comes from the fact that it not only
  reveals how well an architecture satisfies
  particular quality goals but it also provides
  insight into how quality goals interact with each
  other - how they trade off against each other.

3
Presentation Step

• Present the ATAM The evaluation leader
  describes the evaluation methods to the team
  tries to set there expectations and answers
  questions.
• 2) Present the business drivers A project
  decision maker presents a system overview from a
  business perspective. What business goals are
  motivating the development effort and hence what
  will be the primary architecture drivers.

4
Presentation Step

• 3) Present the architecture In this presentation
  the architecture should cover
• Technical constraints such as operating system,
  hardware, or middleware prescribed for use.
• Other Systems with which the systems must
  interact.
• Architectural approaches used to meet quality
  attribute requirement.

5
Investigation and Analysis Step

• 4) Identify the architectural approaches
• The architectural approaches define the
  important structures of the system and describes
  in which the system can grow, respond to changes,
  withstand changes, withstand attacks, integrate
  with other systems and so forth.
• 5) Generate the quality attribute utility tree
• Utility trees provide a mechanism for directly
  and efficiently translating the business drivers
  of a system into concrete quality attribute
  scenarios.
• Participants prioritize the utility tree along
  two dimensions
• By the importance of scenario to the success of
  the system.
• By the degree of difficulty posed by the
  achievement of the scenario.

6
Investigation and Analysis Step
7
Testing

• 7) Brainstorm and prioritize Scenarios
• The brainstorming is done based on three kinds
  of scenarios
• Use case scenarios The way in which stakeholders
  expect the system to be used.
• Growth Scenario Revolves around expected
  modification, changes in performance or
  availability porting to other platforms,
  integration with other software and so forth.
• Exploratory scenarios Dramatic new performance
  or availability requirements.

8
Testing

• At this point one of the three things may
  happen
• The scenario will match and essentially duplicate
  an already existing leaf node.
• The scenario will go into a new leaf node of an
  already existing branch.
• The scenario will fit into no branch of the tree
  because it expresses a quality attribute not
  previously accounted for.
• 8) Analyze the architectural approaches
• Once all the scenarios have been collected and
  analyzed the evaluation team guides the architect
  in the process of carrying out the highest ranked
  scenarios from the previous step.

9
Reporting

• 9) Present the results
• Identifying themes and then relating them to
  specific drivers precipitates two effects
• It brings the evaluation full circle by relating
  the final results to the initial presentation.
• It elevates the risks that were uncovered to the
  attention of the management.

10

• Thank You