Midterm Material - Software Process and Process Models

Question 1

What is a software process?

Answer 1

A structured set of activities required to develop a software system.

Question 2

What do all software processes involve?

Answer 2

Specification - Defining what the system should do
Design and implementation - defining the organization of the system and implementing the system
Validation - Checking that the system does what the customer wants
Evolution - Changing the system in response to customer needs

Question 3

What is a process model?

Answer 3

An abstract representation of a process.

Question 4

What is the difference between a process and a process model?

Answer 4

A layer of abstraction similar to the difference between an abstract data type (ADT) and the implemented data type. For example, waterfall is an abstract model that a company can implement as a process to suit their needs.

Question 5

What is a software process description?

Answer 5

Talking about the activities to be performed within the process and the ordering of the activities. They may also include products, the outcomes of a process activity, and roles, which reflect the responsibilities of the people involved with the process.

Question 6

What is the difference between plan-driven and agile processes?

Answer 6

In plan driven, all process activities are planned in advance and progress is then measured against it. In agile, planning is incremental. It is easier to change the process to reflect different customer requirements.

Question 7

What is the advantage of the incremental planning of agile models?

Answer 7

Makes it easier to make changes based on client feedback without needing to redo a lot of the work.

Question 8

What is the waterfall model?

Answer 8

It is a plan-driven process model with separate and distinct phases of specification and development.

Question 9

What are the stages of the waterfall model?

Answer 9

Requirements definition, system and software design, implementation and unit testing, integration and system testing, operation and maintenance.

Question 10

What is the main problem with the waterfall model?

Answer 10

It is difficult to change anything once the process has begun. In waterfall, a phase must be complete before you can move on so if you’ve made a mistake it’s hard to go back.

Question 11

When should a waterfall model be used?

Answer 11

When requirements are well understood and changes will be limited during the design process. Also for large systems engineering project where a system is developed at several sites.

Question 12

What are some other problems with the waterfall model?

Answer 12

The client only sees a working product once the entire thing has been coded. This can be a problem because they may have not described what they really want.

Question 13

What is an incremental development model?

Answer 13

A model where specification, development, and validation are happening concurrently. Could be plan-driven or agile.

Question 14

What are the stages and products of an incremental development model?

Answer 14

Specification, development, and validation are the stages that happen concurrently. The products produced are the initial version, intermediation versions, and the final version of the product. The initial and intermediate versions provide feedback to improve the product.

Question 15

What are the benefits of an incremental development model?

Answer 15

It doesn’t cost as much to accommodate changes as the amount of analysis and documentation that would have to be redone is reduced.

Makes it easier to get customer feedback. Because of the production of prototypes customers can comment on demonstrations of the software.

More rapid delivery and deployment of useful software is possible.

Question 16

What are the drawbacks of an incremental development model?

Answer 16

The process is not as visible to managers since not as much documentation is produced. This makes it more difficult to track progress.

System structure degrades as new increments are added. This happens because the additional build has to be incorporated without destroying what is already there.

Question 17

What is a reuse-oriented model?

Answer 17

A process where the system is put together from existing components. The components can be configured to make them fit the particular user requirements

Question 18

What are some examples of reusable software?

Answer 18

Stand alone applications configured for use in a particular environment. Ex: different versions of WindowsOS for enterprise or home use.

Collections of objects developed as a package to be integrated with a component framework.

Web services developed according to service standards available for remote invocation. Ex: REST APIs.

Question 19

What are the stages of a reuse oriented process?

Answer 19

Requirements specification, software discovery and evaluation where old software is found that meets the criteria for the current application. Requirements refinement where the requirements are adjusted if necessary. If the application system is available it can be directly integrated but if only the components are available, the components will need to be adapted, new components will need to be added, and then the system can be integrated.

Question 20

What are the advantages of reuse-oriented models?

Answer 20

Reduced costs as not as much software is being built from scratch.

Faster delivery and deployment of the system.

Question 21

What are the drawback of reuse-oriented models?

Answer 21

Requirements compromises need to be made to make existing components fit so the system may not meet the needs of users.

You lose control of the evolution of the reused elements.

Question 22

What are the 4 basic process activities?

Answer 22

Specification, development, validation, and evolution

Question 23

What is requirements engineering?

Answer 23

Establishing what services are required and the constraints on the system’s operation and development

Question 24

What is software design and implementation?

Answer 24

Design is coming up with a structure that realizes the specification. Implementation is taking the design and translating it into an executable program. Together, they convert system specifications into executable systems.

Question 25

What are the inputs, activities, and outputs of the design process?

Answer 25

Inputs: Platform information, requirements specification, data description

Activities: architectural design, interface design, component design, database design

Outputs: System architecture, database specification, interface specification, component specification

Question 26

What is architectural design?

Answer 26

Identifying overall structure of the system, principal components, how they are related, and how they are distributed

Question 27

What is database design?

Answer 27

You design the system data structures and how they are represented in a database

Question 28

What is interface design?

Answer 28

Defining the interfaces between the components

Question 29

What is component design

Answer 29

Designing the individual components of the system.

Question 30

How is a system implemented?

Answer 30

By developing a program or by configuring an application system. However, there is no standard process to programming.

Question 31

What is the goal of verification and validation?

Answer 31

To show that a system conforms to specification and meets the requirements of the customer.

Question 32

What is the most common verification and validation activity?

Answer 32

Testing

Question 33

What are the stages of testing?

Answer 33

Component testing, system testing, acceptance testing

Question 34

What is component testing?

Answer 34

Testing individual components independently. Components can be defined as functions, objects, or groupings of them.

Question 35

What is system testing?

Answer 35

Testing the whole system, all components together

Question 36

What is acceptance testing?

Answer 36

Testing the system with customer data to ensure the system meets customer needs.

Question 37

What is the purpose of software evolution?

Answer 37

As business requirements change, the software that supports the business must change as well. Fewer and fewer systems are completely new so evolving it to meet changing needs is important.

Question 38

What are the inputs, activities, and outputs of software evolution?

Answer 38

Inputs: existing systems
Activities: defining system requirements, assessing existing systems, proposing system changes, modifying the system
Outputs: New system

Question 39

What is change anticipation?

Answer 39

Having the software process include activities that predict changes before rework is required. An example of this would be producing a prototype to show key features so if the changes can be provoked early on.

Question 40

What is change tolerance?

Answer 40

When the software process is designed so changes can be made at a low cost. This usually involves a form of incremental development since you won’t have to go back and change documentation every time something changes.

Question 41

What is a prototype?

Answer 41

An initial version of a system to demonstrate concepts and try out design options.

Question 42

What are the benefits of prototyping?

Answer 42

Improved system usability, closer matching real users needs, improved design quality, improved maintainability, reduced development effort.

Question 43

What are the activities and products of prototype development?

Answer 43

Activities: establish prototype objectives, define prototype functionality, develop prototype, evaluate prototype.

Products: prototyping plan, outline definition, executable prototype, evaluation report

Question 44

What info should a prototype include?

Answer 44

Only the areas of the product that are not well understood since we are prototyping to resolve details. Error checking and recovery may or may not be included. Focusing on functional requirements rather than non-functional

Question 45

Should a prototype be used as a base for the rest of the software? Why or why not?

Answer 45

No, a prototype should be discarded after it is finished and new software built in its place. This is because the prototype structure is typically heavily degraded, it won’t meet organizational quality standards, and it might not be feasible to modify the system to meet the non-functional requirements since we weren’t focusing on them.

Question 46

What are the steps in the process improvement cycle?

Answer 46

Measurement, analysis, change

Question 47

What is process measurement?

Answer 47

Measure an attribute of the software process to form a baseline to see if process improvements are effective

Question 48

What is process analysis?

Answer 48

Assessing the current process to find process weaknesses and bottlenecks

Question 49

What is process change?

Answer 49

Proposing changes to address the weaknesses found in analysis

Question 50

What type of data should be collected on processes?

Answer 50

Quantitative data. Time taken for process activities, resources required, number of defects, etc.

Question 51

What are the 5 stages of the SEI Capability Maturity Model and what do they mean?

Answer 51

1. Initial - the process is unpredictable, poorly controlled, and reactive
2. Repeatable - Processes are made for specific projects but there is no organization wide process and so the organization is often reactive as a whole.
3. Define - You have defined a process at the organization level but the projects may change the process to meet specifics
4. Managed - You are measuring the process and analysing the data
5. Optimizing - Using the collected data to make changes to the processes

Question 52

What is the rational unified process?

Answer 52

A generic process for object-oriented models. It is designed and documented using Unified Modelling Language. it is iterative and incremental.

Question 53

What are the phases of the rational unified process?

Answer 53

Inception - establish the business case for the system
Elaboration - develop understanding of the problem domain and system architecture
Construction - system design, programming, and testing
Transition - Deploy the system in its operating environment

Question 54

What are the five core workflows of the Unified Process?

Answer 54

Requirements, analysis, design, implementation, and test. Each phase has all of the workflows in different amounts

Question 55

What are the six Unified Process best practices?

Answer 55

1. Develop software iteratively - plan increments based on customer priorities with high priority items coming first.
2. Manage requirements - explicitly document customer requirements and keep track of changes
3. Use component-based architecture - organize the system out of reusable components
4. Visually model software - use UML models to present static and dynamic views of the software
5. Continuously verify quality - performing testing throughout the project
6. Control changes - manage changes using a change management system and configuration management tools.