1. Chapter 2 Software Process: A Generic View

2. Quick Look What is software process Who does the process
A series of predictable steps that helps you create a timely, high-quality result.
Who does the process
Software engineers and their managers adapt the process to their needs and then follow it

3. Quick Look (cont.) Why is it important What are the steps
It provides stability, control, and organization to an activity that can, if left uncontrolled, become quite chaotic
What are the steps
At a detailed level, the process that you adopt depends on the software you’re building

4. Quick Look (cont.) What is the work product
Programs, documents, and data
How do I ensure that I’ve done it right
Employing software process assessment mechanisms
Indicators
Quality, timeliness, long-term viability

5. Software engineering Fritz Bauer, 1969 IEEE, 1993
The establishment and use of sound engineering principles in order to obtain economically software that is reliable and works efficiently on real machines
IEEE, 1993
The application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software; that is, the application of engineering to software

6. Software Engineering is a Layered Technology
tools
methods
process model
a “quality” focus

7. Layered Technology (cont.)
Any engineering approach must rest on an organizational commitment to quality
Software process is the glue that holds the technology layers together and enables rational and timely development of computer software

8. Layered Technology (cont.)
Software engineering methods provide the technical how-to’s for building software
Communication, requirement analysis, design modeling, program construction, testing, and support
Software engineering tools provide automated or semi-automated support for the process and the methods
CASE (Computer-Aided Software Engineering)

9. A Generic View of Software Engineering
The work associated with software engineering can be categorized into three generic phases
The definition phase focuses on what
The development phase focuses on how
The support phase focuses on change associated with correction, adaptation, enhancement, and prevention

10. A Process Framework Process framework Framework activities work tasks
work products
milestones & deliverables
QA checkpoints
Umbrella Activities

11. Framework Activities Communication Planning Modeling Construction
Analysis of requirements
Design
Construction
Code generation
Testing
Deployment

12. Umbrella Activities Software project management
Formal technical reviews
Software quality assurance
Software configuration management
Document preparation and production
Reusability management
Measurement
Risk management

13. The Process Model: Adaptability
the framework activities will always be applied on every project ... BUT
the tasks (and degree of rigor) for each activity will vary based on:
the type of project (an “entry point” to the model)
characteristics of the project
common sense judgment; concurrence of the project team

14. The CMMI
Software Engineering Institute (SEI) at Carnegie Mellon University
Capability Maturity Model Integration (CMMI) for determining an organization’s current stat of process maturity
The CMMI defines each process area in terms of “specific goals” and the “specific practices” required to achieve these goals.
Specific goals establish the characteristics that must exist if the activities implied by a process area are to be effective.
Specific practices refine a goal into a set of process-related activities.

15. The CMMI (cont.) One model, two representations
Staged: organizational maturity approach
Continuous: process capability approach

16. The CMMI (cont.)

17. The CMMI (cont.) 5 levels Initial Managed Defined
Quantitatively managed
Optimized

18. outcome depends on individuals
1. Initial
Process:
undefined,
ad hoc
Result:
outcome depends on individuals
Lacking: any reasonable process

19. tracks documents, cost, schedule, functionality (after fact) Result
1. INITIAL Process undefined, ad hoc, depends on individuals
2. Managed
Process
tracks documents, cost, schedule,
functionality (after fact)
Result
repeatable only on similar projects
Lacking: complete process

20. Lacking: predictable outcomes
2. REPEATABLE Basic project management to
track cost & schedule, repeatable on similar projects
3. Defined
Process
documented,
standardized,
tailorable
Result
consistency
Lacking: predictable outcomes

21. 4. Quantitatively managed
3. DEFINED Consistent: Documented, standardized, tailorable
4. Quantitatively managed
Process
detailed measurement; control
Result
process and products with
quantified quality predictability
Lacking mechanism for process improvement

22. Continual process improvement through quantitative feedback;
4. MANAGED Predictable: process & products measured
5 Optimized
Process
Continual process improvement
through quantitative feedback;
Extensible scope
Innovative ideas and technologies
Graphics reproduced with permission from Corel.

23. The CMMI (cont.)
The SEI has associated key process areas (KPAs) with each of the maturity levels
The KPAs describe those software engineering functions that must be present to satisfy good practice at a particular level

24. The CMMI (cont.)
Each KPA is described by identifying the following characteristics
Goals
Commitments
Abilities
Activities
Methods for monitoring implementation
Methods for verifying implementation

25. The CMMI (cont.)
18 KPAs are defined across the maturity model and mapped into different levels of process maturity
Level 2
Software configuration management, software quality assurance, software subcontract management, software project tracking and oversight, software project management, requirement management
Level 3 …

26. Process Areas for CMMI

27. Process Patterns
Process patterns define a set of activities, actions, work tasks, work products and/or related behaviors
A template is used to define a pattern
An example process pattern template proposed by Ambler in 1998
Pattern name
Intent
Type
Initial context
Problem
Solution
Resulting context
Related patterns
Known uses/examples

28. Process Patterns (cont.)
Typical examples:
Customer communication (a process activity)
Analysis (an action)
Requirements gathering (a process task)
Reviewing a work product (a process task)
Design model (a work product)

29. Process Assessment
The process should be assessed to ensure that it meets a set of basic process criteria that have been shown to be essential for a successful software engineering.
Many different assessment options are available:
SCAMPI
CBA IPI
SPICE (ISO/IEC15504)
ISO 9001:2000
Plan-do-check-act

30. Assessment and Improvement

31. Personal Software Process (PSP)
What is it
Developed by a team leaded by W.S. Humphrey in 1995 at CMU/SEI
PSP is a software engineering methodology by which an individual software developer can continuously improve his or her abilities, in particular:
learn to make accurate predictions of time required and quality obtained;
improve the quality of the software produced;
learn how to evaluate technology and methods.
Source:

32. Personal Software Process (cont.)
Recommends five framework activities:
Planning
High-level design
High-level design review
Development
Postmortem

33. Personal Software Process (cont.)
PSP emphasizes the need to record and analyze the types of errors you make, so you can develop strategies to eliminate them
PSP represents a disciplined, metrics-based approach to software engineering

34. PSP Defect Type Standard
Class
Description 10
Documentation problem: documents, comments, or messages are misunderstandable or wrong FIX: correct the document, the comment, or the message 20
Syntax/Static problem: a defect that can USUALLY be detected by the compiler (syntax errors, missing declarations etc. Defects that the compiler has caught only by luck count in other classes!) FIX: correct syntactic or compiler-findable static semantic defect. 30
Build/Package problem: errors in version control or in change management FIX: create or use correct version or correct the change 40
Assignment problem: one-statement defects in data management or procedure calls (e.g. wrong operand or operator in expression, wrong object assigned to, assignment missing or duplicated, call to wrong procedure, call missing) FIX: correct one statement

35. Team Software Process (TSP)
What is it
TSP provides a defined process framework for managing, tracking and reporting the team's progress.
Using TSP, an organization can build self-directed teams that plan and track their work, establish goals, and own their processes and plans.

36. Team Software Process (cont.)
TSP defines the following framework activities:
Launch
High-level design
Implementation
Integration and test
Postmortem
TSP makes a wide variety of scripts, forms, and standards to guide team members
For example, scripts for project launch

37. Team Software Process (cont.)

38. PSP, TSP, and CMMI

39. The Primary Goal of Any Software Process: High Quality
Remember:
High quality = project timeliness
Why?
Less rework!