SOFTWARE PROCESSES

Question 1

Give examples of project constraints

Answer 1

staff, money, time, computing resources,

Question 2

Describe project planning

Answer 2

Project planning is the art of scheduling the necessary activities, in time, space and across staff in order to have in mind:
 project risk
 profit
 customer satisfaction
 worker satisfaction
 long-tern company goals

Question 3

What information must a project plan include?

Answer 3

 resources needed (people, money, equipment, etc)
 dependency & timing of work (flow graph, work packages)
 rate of delivery (reports, code, etc)

Question 4

Give examples of deliverables an SE project must produce to make it more visible

Answer 4

 Design documents/ prototypes
 Reports
 Project/status meetings
 Client surveys (e.g. satisfaction level)

Question 5

What is a software process?

Answer 5

A structured set of activities required to develop a
software system

Question 6

What steps are a part of all software processes?

Answer 6

 Specification – defining what the system should do;
 Design and implementation – defining the organization of the system and implementing the system;
 Validation – checking that it does what the customer wants;
 Evolution – changing the system in response to changing customer needs.

Question 7

What is a software process model?

Answer 7

A software process model is an abstract representation
of a process. It presents a description of a process from
some particular perspective.

Question 8

What do software descriptions entail

Answer 8

 Activities in these processes such as specifying
a data model, designing a user interface, etc. and the
ordering of these activities
 Products, which are the outcomes of a process activity;
 Roles, which reflect the responsibilities of the people
involved in the process;
 Pre- and post-conditions, which are statements that are true before and after a process activity has been enacted or a product produced.

Question 9

What are the different types of software process models

Answer 9

 Plan-driven processes are processes where all of the
process activities are planned in advance and progress
is measured against this plan. AKA Heavy-weight

 In Agile Processes planning is incremental and it is
easier to change the process to reflect changing customer requirements. AKA Light-Weight

Question 10

Give examples of Heavy-Weight models

Answer 10

Waterfall Model
Boehm’s Spiral Model
V-shaped Model

Question 11

Describe the waterfall model

Answer 11

 Separate and distinct phases of specification and development.
 Heavily oriented toward documentation (documentation-intensive)
 Progress often measured through documentation completion and reviews (many)
 Gantt charts
 Lockstep approach

Question 12

Illustrate the different phases of the waterfall method

Answer 12

*See notes

Question 13

What are some of the problems involved with waterfall models

Answer 13

Inflexible partitioning of the project into distinct stages
makes it difficult to respond to changing customer
requirements.
But many issues are true too, such as risk addressing.

Question 14

In which situations is the waterfall model used?

Answer 14

 This model is only appropriate when the requirements are well-understood and changes will be fairly limited during the design process.
 The waterfall model is mostly used for large systems
engineering projects where a system is developed at
several sites.
 In those circumstances, the plan-driven nature of the waterfall model helps coordinate the work.

Question 15

Describe the Boehm’s spiral model

Answer 15

 Process is represented as a spiral rather than as a
sequence of activities with backtracking.
 Each loop in the spiral represents a phase in the process.
 No fixed phases such as specification or design - loops in the spiral are chosen depending on what is required.
 Risks are explicitly assessed and resolved throughout the process.
 This was the motivation behind developing the Spiral Model - Risk

Question 16

Illustrate the Boehm’s Spiral Model

Answer 16

*See notes

Question 17

What are the sectors of the spiral model sectors?

Answer 17

 Objective setting
Specific objectives for the phase are identified.
 Risk assessment and reduction
Risks are assessed and activities put in place to reduce
the key risks.
 Development and validation
A development model for the system is chosen which
can be any of the generic models. Development takes
place.
 Planning
The project is reviewed and the next phase of the spiral
is planned.

Question 18

In what situations in the spiral model used?

Answer 18

 Spiral model has been very influential in helping people think about iteration in software processes and
introducing the risk-driven approach to development
 In practice, however, the model is rarely used as
published for practical software development

Question 19

Describe the V-Shaped Model

Answer 19

 A variant of the Waterfall that emphasizes the
verification and validation of the product.
 Testing of the product is planned in parallel with a
corresponding phase of development.

Question 20

Illustrate the v-shaped model

Answer 20

*See notes for illustration and explanations of the steps

Question 21

What are the strengths of the V-Shaped model

Answer 21

 Emphasize planning for verification and validation of the product in early stages of product development
 Each deliverable must be testable
 Project management can track progress by milestones
 Easy to use

Question 22

What are the weaknesses of the V-Shaped model

Answer 22

 Does not easily handle concurrent events
 Does not handle iterations or phases
 Does not easily handle dynamic changes in requirements
 Does not contain risk analysis activities

Question 23

When is the V-Shaped Model used?

Answer 23

 Excellent choice for systems requiring high reliability eg hospital patient control applications
 All requirements are known up-front
 When it can be modified to handle changing requirements beyond analysis phase
 Solution and technology are known.

Question 24

What are the disadvantages of Heavy-Weight models in general

Answer 24

Delivered late,
Over budget,
Failure to meet functional and non-functional requirements,
Not responsive to change,
Poor assessment of risk,
Discovery of major problems late