Software Process, PM Process Groups, Links, PM Phase interactions

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Initiating Process: Inputs, Outputs, Tools and Techniques >>

Software Project Management (CS615)

Figure 1: Quality Assurance

LECTURE # 20

3. Processes

3.1

Software Process

When you build a product or system, it's important to go through a series of

predictable steps a road map that helps you create a timely, high-quality result,

The road map that you follow is called a 'software process' .

Software engineers and their managers adapt the process to their needs and then

follow it. In addition, the people who have ties defined by the process requested

the software play a role in the software process.

It provides stability, control, and organization to an activity that can, if left

uncontrolled, become quite chaotic.

At a detailed level, the process that you adopt depends on the software you're

building. One process might be appropriate for creating software for an aircraft

avionics system, while an entirely different process would be indicated for the

creation of a web site.

From the point of view of a software engineer, the work products are the

programs, documents and data produces as a consequence of the software

engineering activities defined by the process.

A number of software process assessment mechanisms enable organizations to

determine the "maturity" of a software process. However, the quality, timeliness

and long-term viability of the product you build are the best indicators of the

efficacy of the process that you use.

A common process framework is established by defining a small number of

framework activities that are applicable to all software projects, regardless of their

size or complexity. A number of task sets-each a collection of software

engineering work tasks, project milestones, work products, and quality assurance

points enable the framework activities to be adapted to the characteristics of the

software project and the requirements of the project team. Finally, umbrella

activities-such as software quality assurance, software configuration management,

and measurement - overlay the process model. Umbrella activities are

independent of anyone framework activity and occur through- out the process.

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Common process

Framework activities

Tasks

Milestones,

SQA points

Figure 1: The software Process

⇒ Software Process Vs Software Engineering

But what exactly is a software process from a technical point of view? A software

process is a framework for the tasks that are required to build high-quality

software. Is process synonymous with software engineering? The answer is "yes"

and "no." A software process defines the approach that is taken as software is

engineered. But software engineering also encompasses technologies that

populate the process-technical methods and automated tools.

More important, software engineering is performed by creative, knowledgeable

people who should work within a defined and mature software process that is

appropriate for the products they build, and the demands of their marketplace.

⇒ Software Engineering

Software engineering is a layered technology. Referring to Figure 2, any

engineering approach (including software engineering) must rest on an

organizational commitment to quality. Total quality management and similar

philosophies foster a continuous process improvement culture, and this culture

ultimately leads to the development of increasingly more mature approaches to

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Software Project Management (CS615)

software engineering. The bedrock that supports software engineering is a quality

focus.

Figure 2: Software engineering layers

Process

A quality focus

Tools

Metho

The foundation for software engineering is the process layer. Software

engineering process is the glue that holds the technology layers together and

enables rational and timely development of computer software. Process defines a

framework for a set of key process areas that must be established for effective

delivery of software engineering technology.

The key process areas form the basis for management control of software projects

and establish the context in which technical methods are applied, work products

(models, documents, data, reports, forms, etc.) are produced, milestones are

established, quality is ensured, and change is properly managed.

Software engineering methods provide the technical how-to's for building

software. Methods encompass a broad array of tasks that include requirements

analysis, design, program construction testing and support. Software engineering

methods rely on a set of basic principles that govern each area of the technology

and include modeling and other descriptive techniques.

Software engineering tools provide automated or semi-automated support for the

process and the methods. When tools are integrated so that information created by

one tool can be used by another, a stem for the support of software development

called computer-aided software engineering, is established. CASE combines

software, hardware, and a software engineering database (a repository containing

important information about analysis, design, program construction and testing) to

create software engineering environment analogous to CAD/CAE (computer-

aided design engineering) for hardware.

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3.2

PM Process Groups

Project management processes can be organized into five groups of one or more

processes each:

1. Initiating processes--authorizing the project or phase

2. Planning processes--defining and refining objectives and selecting the best

of the alternative courses of action to attain the objectives that the project

was undertaken to address

3. Executing processes--coordinating people and other resources to carry out

the plan

4. Controlling processes--ensuring that project objectives are met by

monitoring and measuring progress regularly to identify variances from plan

so that corrective action can be taken when necessary

5. Closing processes--formalizing acceptance of the project or phase and

bringing it to an orderly end

Each process is described by:

Inputs

Tools & Techniques

Outputs

3.3

PM Process Links

The process groups are linked by the results they produce--the result or out-

come of one often becomes an input to another.

Among the central process groups, the links are iterated--planning provides

executing with a documented project plan early on, and then provides documented

updates to the plan as the project progresses. These connections are illustrated in

Figure 3.

The project management process groups are not discrete, one-time events; they

are overlapping activities that occur at varying levels of intensity throughout each

phase of the project. These process groups overlap and vary within a phase.

Figure 4 illustrates how the process groups overlap and vary within a phase.

3.4

PM Phase interactions

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Finally, the process group interactions also cross phases such that closing one

phase provides an input to initiating the next. For example, closing a design phase

requires customer acceptance of the design document. Simultaneously, the design

document defines the product description for the ensuing implementation phase.

This interaction is illustrated in Figure 5. Repeating the initiation processes at the

start of each phase helps to keep the project focused on the business need that it

was undertaken to address. It should also help ensure that the project is halted if

the business need no longer exists, or if the project is unlikely to satisfy that need.

It is important to note that the actual inputs and outputs of the processes depend

upon the phase in which they are carried out. Although Figure 5 is drawn with

discrete phases and discrete processes, in an actual project there will be many

overlaps. The planning process, for example, must not only provide details of the

work to be done to bring the current phase of the project to successful completion,

but must also provide some preliminary description of work to be done in later

phases. This progressive detailing of the project plan is often called rolling wave

planning; indicating that planning is an iterative and ongoing process.

Involving stakeholders in the project phases generally improves the probability of

satisfying customer requirements and realizes the buy-in or shared ownership of

the project by the stakeholders, which is often critical to project

success.

Initiating

Planning

Processes

Controlling

Executing

Processes

Closing

Processes

Figure 3: Links among Process Groups in a phase

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Executing

Processes

Planning

Processes

Initiating

Closing Processes

Processes

Controlling

Processes

Phase

Start

Finish

Figure 4: Overlap of Process Groups in a Phase

Design Phase

Implementation Phase

Initiating

Planning

Initiating

Planning

Controlling

Executing

Closing

Figure 5: Interaction between phases

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