1. Embedded Systems Software Training Center
Software Life Cycle
Copyright © 2011 DSR Corporation

2. Welcome Instructor Introduction Objectives and Content Class Materials
Agenda
Copyright © 2011 DSR Corporation

3. Instructor Introduction
Alexandr Bychkov
VP of Engineering at DSR
Copyright © 2011 DSR Corporation

4. Objectives Understand what we mean by a “process”
Understand software development products, processes, and resources
Understand the various models of the software development process
Understand the tools and techniques used for process modeling
Copyright © 2011 DSR Corporation

5. Class Materials
Software Engineering Introduction presentation is available here:
Hands-on Exercises are available here:
Copyright © 2011 DSR Corporation

6. Agenda The Meaning of Process Software Process Models
Tools and Techniques for Process Modelling
Practical Process Modelling
Copyright © 2011 DSR Corporation

7. 1. The Meaning of Process

8. 1. The Meaning of Process
A process: a series of steps involving activities, constraints, and resources that produce an intended output of some kind
A process involves a set of tools and techniques
Copyright © 2011 DSR Corporation

9. 1. The Meaning of Process Process Characteristics
Prescribes all major process activities
Activities are organized in sequence, so timing is clear
Each process has guiding principles, including goals of each activity
Each process activity has entry and exit criteria
May be composed of subprocesses with hierarchy or links
Produces intermediate and final products
Resources:
Environment, tools
Human effort and experience
Constraints may apply to an activity, resource or product
Copyright © 2011 DSR Corporation

10. 1. The Meaning of Process The Importance of Processes
Impose consistency and structure on a set of activities
Guide us to understand, control, examine, and improve the activities
Enable us to capture our experiences and pass them along
Copyright © 2011 DSR Corporation

11. 2. Software Process Models

12. 2. Software Process Models Software Life Cycle Process
When a process involves building a software, the process may be referred to as a software lifecycle
Activities (sub-processes):
Requirements analysis and definition
System (architecture and high level) design
Program (low level) design
Writing programs (coding/implementation)
Testing:
unit
integration
system
System delivery (deployment)
Maintenance
Copyright © 2011 DSR Corporation

13. 2. Software Process Models Software Life Cycle Processes by IEEE/EIA 12207.0
Primary lifecycle processes:
Development process
Acquisition process
Supply process
Operation process
Maintenance process
Supporting lifecycle processes:
Audit process
Configuration Management
Joint review process
Documentation process
Quality assurance process
Problem solving process
Verification process
Validation process
Organizational processes:
Management process
Infrastructure process
Improvement process
Training process
Copyright © 2011 DSR Corporation

14. 2. Software Process Models Software Development Process Models
Waterfall model
V model
Prototyping model
Spiral model
Transformational model
Phased development: increments and iterations
Agile methods
Rapid application development (RAD)
Cowboy coding
Copyright © 2011 DSR Corporation

15. 2. Software Process Models Waterfall Model
Copyright © 2011 DSR Corporation

16. 2. Software Process Models Waterfall Model Specifics
One of the first process development models proposed (1970, article by Winston W. Royce)
Works for well understood problems with minimal or no changes in the requirements
Simple and easy to explain to customers
It presents
a very high-level view of the development process
sequence of process activities
Each major phase is marked by milestones and deliverables (artefacts)
Copyright © 2011 DSR Corporation

17. 2. Software Process Models Drawbacks of the Waterfall Model
Provides no guidance on how to handle changes to products and activities during development (assumes requirements can be frozen)
Doesn’t allow to evaluate the requirements feasibility
Doesn’t contain the bug fixing activity
Views software development as a manufacturing process rather than as a creative process
There are no iterative activities that lead to creating a final product
Long wait before the final product
Copyright © 2011 DSR Corporation

18. 2. Software Process Models V Model
Copyright © 2011 DSR Corporation

19. System Engineering Process
2. Software Process Models Specific of Embedded System Development Process
System Engineering Process
System Requirements Definition
System Test
System Architecture Design
System Integration and System Integration Test
Software Requirements Definition
Comprehensive Software Testing
Software Architecture Design
Integration and Software Testing and Software Integration
Detailed Software Design
Unit Test
Software Engineering Process
Implementation
Copyright © 2011 DSR Corporation

20. 2. Software Process Models Prototyping Model
Allows repeated investigation of the requirements or design
Reduces risk and uncertainty in the development
Very helpful for
UI specification
Proof-of-concept
Copyright © 2011 DSR Corporation

21. 2. Software Process Models Spiral Model – Minimization and Control of Risk
Copyright © 2011 DSR Corporation

22. 2 Software Process Models Transformational Model
Copyright © 2011 DSR Corporation

23. 2. Software Process Models Phased Development: Increments and Iterations
Copyright © 2011 DSR Corporation

24. 2. Software Process Models Phased Development: Increments and Iterations (cont.)
Incremental development: starts with a small functional subsystem and adds functionality with each new release
Iterative development: starts with a full system, then changes functionality of each subsystem with each new release
Copyright © 2011 DSR Corporation

25. 2. Software Process Models Phased Development
Phased development is desirable for several reasons:
It enables customers to have some functionality while the rest is being developed
Training can begin early, even though some functions are still in progress
Frequent releases allow developers to fix unanticipated problems globally and quickly
The development team can focus on different areas of expertise with different releases
Copyright © 2011 DSR Corporation

26. 2. Software Process Models Agile Methods
Emphasis on flexibility in producing software quickly and capably
Agile manifesto:
Value individuals and interactions over process and tools
Prefer to invest time in producing working software rather than in producing comprehensive documentation
Focus on customer collaboration rather than contract negotiation
Concentrate on responding to change rather than on creating a plan and then following it
Copyright © 2011 DSR Corporation

27. 2. Software Process Models Agile Methods: Examples of Agile Process
Extreme programming (XP)
Scrum: 30-day iterations; multiple self-organizing teams; daily “scrum” coordination
Feature-driven development (FDD):  driven from a client-valued functionality (feature) perspective
Adaptive software development (ASD)
Copyright © 2011 DSR Corporation

28. 2. Software Process Models Agile Methods: Twelve Facets of XP
The planning game (customer defines value)
Small releases
Metaphor (common vision, common names)
Simple design
Writing tests first
Refactoring
Pair programming
Collective ownership
Continuous integration (small increments)
Sustainable pace (40 hours/week)
On-site customer
Coding standards
Copyright © 2011 DSR Corporation

29. 2. Software Process Models Agile Methods: Scrum
Roles:  “Scrum Master”, “Product Owner”, “Team”
A sprint is the basic unit of development in Scrum
“backlog”, which is a prioritized set of high level requirements of work to be performed
Meetings: Daily Stand-ups, Sprint Planning Meeting, Sprint Review Meeting
Copyright © 2011 DSR Corporation

30. 2. Software Process Models Agile Methods: RAD
RAD uses minimal planning in favor of rapid prototyping
It involves methods like iterative development and software prototyping
Rad involves Joint Application Development (JAD) techniques and CASE tools to translate user needs into working model
Copyright © 2011 DSR Corporation

31. 3. Tools and Techniques for Process Modeling

32. 3. Tools and Techniques for Process Modeling
Notation depends on what we want to capture in the model
The two major notation categories:
Static model: depicts the process
Example: Lai notation
Dynamic model: enacts the process
Marvel Specification Language
Copyright © 2011 DSR Corporation

33. 3. Tools and Techniques for Process Modeling Marvel Case Studies
Signalling Fault Resolution Process
Copyright © 2011 DSR Corporation

34. 3. Tools and Techniques for Process Modeling Example of Marvel Commands
Copyright © 2011 DSR Corporation

35. 4. Practical Process Modeling

36. 4. Practical Process Modeling Example 1: Control Panel
Summary
Data
Sensor
data
Collector
Data processor
Network bridge
Sensor data
CDMS
Reports DB
Web Service UI
Control
Operating System
Hardware
3rd party SW
Copyright © 2011 DSR Corporation

37. 4. Practical Process Modeling Example 1: Control Panel (cont.)
Chosen Process model: Waterfall-based with prototyping and early delivery
Prototyping for:
DBMS choice
Feasibility evaluation
HW limitations
3rd party compatibility
Performance requirements understanding
LLD and implementation in parallel
Early delivery
After unit testing to start system integration
Copyright © 2011 DSR Corporation

38. 4. Practical Process Modelling Example 1: Control Panel (cont.)
REQUIREMENTS ANALYSIS
SYSTEM DESIGN
PROGRAM DESIGN
CODING
UNIT TESTING
EARLY DELIVERY
Prototyping
INTEGRATION TESTING
SYSTEM TESTING
FINAL DELIVERY
MAINTENANCE
Copyright © 2011 DSR Corporation

39. 4. Practical Process Modeling Example 2: Porting
Tasks:
Porting to a new platform
Hardware OS
New features implementation
Process model:
Iterative
Phase 1
Porting to anew platform
Phase 2
New feature implementation
Copyright © 2011 DSR Corporation

40. 4. Practical Process Modeling Example 3: Huge Innovative Web-based System
Details:
The work requires 2 years to implement
Set of main features is clear
Set of supplementary features is not clear
Process model: Iterative
Phase 1: Development of the operable prototype
Engine with basic functions
Basic UI
Phase 2:
Development of the sellable version 1.0 with basic functionality
Phases 3…n
Enhancement of functionality using Scrum
Copyright © 2011 DSR Corporation

41. 4. Practical Process Modeling Example 4: Ariane-5
Reuse process model presentation
Copyright © 2011 DSR Corporation

42. 4. Practical Process Modeling Typical Issues
Customer was not satisfied with results
System developed and tested well on Windows 2008 Server, but customer uses Windows 2008 R2 Server where the main functionality does not work. Issue: incomplete requirements.
Wrong test results
QA team wrongly interpreted design specification so all of the tests failed. Issue: incomplete design.
A developed SW system has good quality but cannot operate on the user’s site because the feature that supports their workflow is not supported.
Issue: incomplete requirements
Copyright © 2011 DSR Corporation

43. Summary
Process development involves activities, resources, and products
Process model includes organizational, functional, behavioural, and other perspectives
A process model must be chosen for every project and product
A process model is useful for guiding team behaviour, coordination, and collaboration
Copyright © 2011 DSR Corporation

44. References
Software Engineering: Theory and Practice / Shari Lawrence Pfleeger
SWEBOK. Guide to the Software Engineering. Body of Knowledge Version / A project of the IEEE Computer Society Professional Practices Committee
IEEE Std , IEEE Standard Glossary of Software Engineering Terminology
IEEE Std IEEE Standard for Developing Software Life Cycle Processes
Copyright © 2011 DSR Corporation