Six Part Scenarios

Introduction

•          Functionality and Quality Attributes are orthogonal

•          Overall factors that affect run-time behavior, system design, and user experience

Architecture and Quality Attributes

•          Architecture, by itself, is unable to achieve qualities

•          Architecture should include the factors of interest for each attribute

Quality Attributes Scenario

Ø   Is a quality-attribute-specific requirement

Ø   It consists of six parts:

•                              Source of stimulus

•                              Stimulus

•                              Environment

•                              Artifact

•                              Response

•                              Response measure

Common Quality Attributes

Ø It categorizes the attributes in various specific areas

•          Design qualities

•          Runtime qualities

•          System qualities

•          User qualities

•          Non-runtime qualities

•          Architecture qualities

•          Business qualities

Ø Conceptual Integrity:

•                             Defines the consistency and coherence of the overall design

•                             Includes the way that components or modules are designed

Ø Maintainability:

•                             Ability of the system to undergo changes with a degree of ease

Ø Reusability:

Defines the capability for components and subsystems to be suitable for use in other applications

Runtime Quality Attributes

Ø Interoperability:

•                            Ability of a system or different systems to operate successfully by communicating and exchanging information with other external systems written and run by external parties

Ø Manageability:

•                            Defines how easy it is for system administrators to manage the application

Ø Reliability:

• Ability of a system to remain operational over time

Ø Scalability:

•                            Ability of a system to either handle increases in load without impact on the performance of the system, or the ability to be readily enlarged

Ø Performance:

•                            Indication of the responsiveness of a system to execute any action

Ø Security:

Capability of a system to prevent malicious or accidental actions outside of the designed usage

Ø Availability:

•          Proportion of time that the system is functional and working

Measured as a percentage of the total system downtime over a predefined period

System Quality Attributes

²            Ø Supportability:

•                             Ability of the system to provide information helpful for identifying and resolving issues when it fails to work correctly

Ø Testability:

Measure of how easy it is to create test criteria for the system and its components

User Quality Attributes

3

Ø Usability:

•          Defines how well the application meets the requirements of the user and consumer by being intuitive

Non-runtime Quality Attributes

Ø Portability:

•                            Ability of a system to run under different computing environments

Ø Reusability:

•                            Degree to which existing applications can be reused in new applications

Ø Integrability:

Ability to make the separately developed components of the system work correctly together

Ø Modifiability:

Ease with which a software system can accommodate changes to its software

Architecture Quality Attributes

Ø Correctness:

•                            Accountability for satisfying all requirements of the system

Ø Conceptual Integrity:

•          Integrity of the overall structure that is composed from a number of small architectural structures

Business Quality Attributes

Ø Cost and schedule:

•                            Cost of the system with respect to time to market, expected project lifetime, and utilization of legacy and COTS systems

Ø Marketability:

• Use of the system with respect to market competition