Lecture 13: Summary The three aspects: - quality - specification - engineering

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Lecture 13 SummaryThe three aspects -
quality - specification - engineering
Spring 2002
Lecturers H. Muccini and D. J. Richardson
ICS 122 Software Specificationand Quality
Engineering
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Software Quality Elements
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Quality
Formal and Semi-formal Spec
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Engineering
Management
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1. Quality
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What is Software Quality?

• Quality Support
• Quality Organization
• Quality Software
• Quality Product
• Quality attributes

Goal Customer Satisfaction
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Distinguishing Qualities

• Security and Integrity
• Expandability (user needs)? Flexibility(new env)
  ? Portability
• Manageability, Maintainability, Survivability
• Usability and Learnability
• What is Correctness?
• Why do we care about qualities?
• Associated Costs
• Why cant we have it all?
• Trade-offs

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In practical contexts

• Sometimes quality is not a primary concept in
  developing software systems, but
• In some contexts, it becomes essential
• Medical Instruments
• Satellite systems
• Air traffic controller
• Systems with millions of LOC

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Software Quality Attributes
Operational
Maintenance

• Functional what the software does
• integrity
• reliability
• survivability
• usability
• Performance how well it does it
• correctness
• efficiency
• safety
• interoperability

• Change modifying the software
• maintainability
• expandability
• flexibility
• portability
• reusability
• Management planning, controlling, testing,
  installation
• verifiability
• manageability

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Software Quality process
Inaccurate Req.
Not only development
Development Process Defects
Support Process defects
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Quality System and Total Quality Management

• Quality policy
• Quality organization
• Cultural and Technical Program
• Procedure and Standards
• Methods and Tools
• Review and evaluate

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Quality Principles

• Error prevention
• Error detection
• Establish and eliminate the causes
• Audit work
• Categories of Software defects

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Quality models and metrics

• Different models
• McCall FCM Model and metrics
• Boehm Model
• Different metrics
• Different types of metrics
• Different methods and Tools

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Quality Standards

• ISO 9000
• CMM
• PSP
• TSP
• Their complexity, cost, advantages and
  applicability

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2. Formal and Semi-Formal SpecificationFormal
vs Semi-Formal?
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Formal Specification

• What are formal specifications
• Mathematical
• Precise
• Abstraction
• Use of Formal specifications
• Why
• Why not
• Who
• When use formal specifications
• Requirements
• Software Architectures
• Design
• Testing
• Formal specification and Software Process

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Types of Formal Specifications

• Behavioral and Structural
• Model-Oriented and Property-Oriented
• Visual and Executable

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Semi-formal specifications and UML

• Goals/advantages of Uml
• Diagrams and Views
• Each diagram focus on a particular aspect or the
  system ? system decomposition in viewpoints
• UML Semantics
• Several weaknesses
• Do you remember this example?

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3. Software Engineering
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Activities and Software Processes

• The Software Process Activities
• Software Processes
• Traditional
• Formal
• The V-model
• Reuse-based
• RUP
• Architecture-based

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Requirements

• User, System and Software Requirements
• Non-functional Requirements and Software Quality
• Activities
• Feasibility, elicitation,
• Specification
• Analysis and validation
• Actual Trend

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Software Architectures

• Different aspects
• Components and connectors
• Structural and Behavioral
• ADL
• Different languages for different purposes
• UML as an ADL
• Analysis
• SA management is expensive and time consuming
• ? maximize the benefits
• ? Analyze SA as much as possible

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General Comments

• Why use these Methods
• Prove it..
• Why dont people use these Methods?
• Costly
• Too hard
• Too much time..
• Do all companies care about quality?
• NO!
• Should all software development focus on quality?
• Maybe. .maybe Not!
• How do we prove reliability without testing for
  years?
• Reuse and OTS are the ots products good?