Chapter 2 - Software Processes
Give an example of what Time is taken for process activities to be completed
Calendar time or effort to complete an activity or process
What does COTS stand for in Software Engineering?
Commercial-off-the-shelf
Although it more rapid delivery and deployment of useful software to the customer is possible using Incremental development in how has software made is rapid for Customers?
Customers are able to use and gain value from the software earlier than is possible with a waterfall process.
What does the Process maturity approach involves
It focuses on improving process and project management and introducing good software engineering practice.
What does the Agile approach involves
It focuses on iterative development and the reduction of overheads in the software process.
How is the Waterfall model a Plan-Driven Model
It has separate and distinct phases of specification and development.
What must we know about the Pre- and post-conditions that are included in the Process descriptions
which are statements that are true before and after a process activity has been enacted or a product produced.
What must we know about the Products that are included in the Process descriptions
which are the outcomes of a process activity
What must we know about the Roles that are included in the Process descriptions
which reflect the responsibilities of the people involved in the process
What are 3 things we must know about discarding Prototypes after development as they are not a good basis for a production system
1, It may be impossible to tune the system to meet non-functional requirements; 2, Prototypes are normally undocumented; 3, The prototype structure is usually degraded through rapid change; 4, The prototype probably will not meet normal organizational quality standards.
What 3 things to know about Software Process Models
1, A structured set of activities is required to develop a software system. 2, There many different software processes involved. 3, A software process model is an abstract representation of a process as It presents a description of a process from some particular perspective.
What are four activities that happen in the Design Activities?
1, Architectural design 2, Database design 3, Interface design 4, Component selection and design
What are 3 characteristic of the Integration and configuration?
1, Based on software reuse where systems are integrated from existing components or application systems 2, Reused elements may be configured to adapt their behavior and functionality to a user's requirements 3, Reuse is now the standard approach for building many types of business system
What are the 3 types of changes that is inevitable in all large software projects.
1, Business changes lead to new and changed system requirements 2, New technologies open up new possibilities for improving implementations 3, Changing platforms require application changes
What 2 changes help in *Reducing the costs of rework*
1, Change anticipation, where the software process includes activities that can anticipate possible changes before significant rework is required. 2, Change tolerance, where the process is designed so that changes can be accommodated at relatively low cost.
What are the 2 things that happen when *coping with change*
1, Change is inevitable in all large software projects. 2, Changing platforms require application changes Change leads to rework so the costs of change include both rework e.g. re-analyzing requirements as well as the costs of implementing new functionality
What are 3 stages of software testing?
1, Component testing 2, System testing 3, Customer testing
What are 4 Incremental delivery advantages
1, Customer value can be delivered with each increment so system functionality is available earlier. 2, Early increments act as a prototype to help elicit requirements for later increments. 3, Lower risk of overall project failure. 4, The highest priority system services tend to receive the most testing.
The process of prototype development
1, Establish prototype 2, Define prototype functionality 3, Develop prototype 4, Evaluate prototype
What are the 5 Benefits of prototyping?
1, Improved system usability. 2, A closer match to users' real needs. 3, Improved design quality. 4, Improved maintainability. 5, Reduced development effort.
What 2 two we must understand about Plan-Driven and Agile Processes?
1, In practice, most practical processes include elements of both plan-driven and agile approaches. 2, There are no right or wrong software processes.
Name two Software Process Model that may be Plan-Driven model or Agile model?
1, Incremental development 2, Integration and configuration
What are the 3, difference Incremental development and delivery
1, Incremental development - Develop the system in increments and evaluate each increment before proceeding to the development of the next increment; While Incremental delivery - Deploy an increment for use by end-users 2, Incremental development - Uses normal approach used in agile methods While Incremental delivery - It is more realistic evaluation about practical use of software 3, Evaluation done by user/customer proxy. While Incremental delivery it it difficult to implement for replacement systems as increments have less functionality than the system being replaced.
What 2 things that happen during the *Component testing* part of the Testing Stage
1, Individual components are tested independently 2, Components may be functions or objects or coherent groupings of these entities.
What are the 5 levels of Capability maturity levels
1, Initial 2, Managed 3, Defined 4, Quantitatively 5, Optimizing
What the 5 phases in The SEI capability maturity model
1, Initial 2, Repeatable 3, Defined 4, Managed 5, Optimizing
What are the 2 way that Prototype development may occur?
1, May be based on rapid prototyping languages or tools 2, May involve leaving out functionality
What are 3 stages of The process improvement cycle
1, Measure 2, Analyze 3, Change
What are the 2 Incremental delivery problems
1, Most systems require a set of basic facilities that are used by different parts of the system. 2, The essence of iterative processes is that the specification is developed in conjunction with the software.
What are the 3 types of Process improvement activities
1, Process measurement 2, Process analysis 3, Process change
What are the 3 functionality that we may involve leaving out during Prototype development
1, Prototype should focus on areas of the product that are not well-understood; 2, Error checking and recovery may not be included in the prototype; 3, Focus on functional rather than non-functional requirements such as reliability and security
What are 3 characteristic of Incremental delivery
1, Rather than deliver the system as a single delivery, the development and delivery is broken down into increments with each increment delivering part of the required functionality. 2, User requirements are prioritized and the highest priority requirements are included in early increments. 3, Once the development of an increment is started, the requirements are frozen though requirements for later increments can continue to evolve.
What are 3 characteristics of Process Activities
1, Real software processes are inter-leaved sequences of technical, collaborative and managerial activities with the overall goal of specifying, designing, implementing and testing a software system. 2, The four basic process activities of specification, development, validation and evolution are organized differently in different development processes. 3, For example, in the waterfall model, they are organized in sequence, whereas in incremental development they are interleaved.
What are two Advantages to the process Stage
1, Reduced costs and risks as less software is developed from scratch 2, Faster delivery and deployment of system
What are 5 separate identified phases in the waterfall model
1, Requirements analysis and definition 2, System and software design 3, Implementation and unit testing 4, Integration and system testing 5, Operation and maintenance
What are the 3 Requirements engineering process?
1, Requirements elicitation and analysis 2, Requirements specification 3, Requirements validation
What are the 5 key process stages in Software Development
1, Requirements specification 2, Software discovery and evaluation 3, Requirements refinement 4, Application system configuration 5, Component adaptation and integration
What are the 3 things that happen during Software evolution?
1, Software is inherently flexible and can change. 2, As requirements change through changing business circumstances, the software that supports the business must also evolve and change. 3, Although there has been a demarcation between development and evolution - maintenance this is increasingly irrelevant as fewer and fewer systems are completely new.
What are 4 different software processes involved?
1, Specification 2, Design and implementation 3, Validation 4, Evolution
What are 3 types of reusable Software
1, Stand-alone application systems that sometimes COTS are configured for use in a particular environment. 2, Collections of objects that are developed as a package to be integrated with a component framework such as .NET or J2EE. 3, Web services that are developed according to service standards and which are available for remote invocation.
What are the 2 requirement we look at when Coping with changing requirements
1, System prototyping, where a version of the system or part of the system is developed quickly to check the customer's requirements and the feasibility of design decisions. This approach supports change anticipation. 2, Incremental delivery, where system increments are delivered to the customer for comment and experimentation. This supports both change avoidance and change tolerance.
What are the 3 benefits of Incremental development
1, The cost of accommodating changing customer requirements is reduced. 2, It is easier to get customer feedback on the development work that has been done. 3, More rapid delivery and deployment of useful software to the customer is possible
What are the problems with Incremental development?
1, The process is not visible. 2, System structure tends to degrade as new increments are added.
What are the 2 approaches to improvement?
1, The process maturity approach 2, The agile approach
What are the 3 ways we use a prototype?
1, The requirements engineering process to help with requirements elicitation and validation; 2, In design processes to explore options and develop a UI design; 3, In the testing process to run back-to-back tests.
What are 4 things that happen during system implementation?
1, The software is implemented either by developing a program or programs or by configuring an application system. 2, Design and implementation are interleaved activities for most types of software system. 3, Programming is an individual activity with no standard process. 4, Debugging is the activity of finding program faults and correcting these faults.
What are the 3 things that occur during *Process Metrics*
1, Time taken for process activities to be completed 2, Resources required for processes or activities 3, Number of occurrences of a particular event
Name 2 reason why many software companies have turned to software process improvement as a way of enhancing the quality of their software
1, To reduce costs 2, accelerating their development processes.
What are 4 things that happen during Software Validation?
1, Verification and validation (V & V) is intended to show that a system conforms to its specification and meets the requirements of the system customer. 2, Involves checking and review processes and system testing. 3, System testing involves executing the system with test cases that are derived from the specification of the real data to be processed by the system. 4, Testing is the most commonly used V & V activity.
What 3 questions must we ask in the Requirements engineering process
1, What do the system stakeholders require or expect from the system during figuring out the Requirements elicitation and analysis? 2, Defining the requirements in detail when figuring out the Requirements specification? 3, Checking the validity of the requirements when figuring out Requirements validation?
What are two things to keep in mind about Software Process Descriptions?
1, When we describe and discuss processes, we usually talk about the activities in these processes such as specifying a data model, designing a user interface, etc. and the ordering of these activities. 2, That the Process descriptions may also include Products, Roles, Pre- and Post Conditions
What 2 things do we measure during Process measurement
1, Wherever possible, quantitative process data should be collected 2, Process measurements should be used to assess process improvements
What are two Disadvantages to the process Stage
1, requirements compromises are inevitable so system may not meet real needs of users 2, Loss of control over evolution of reused system elements
How many Capability maturity levels are there?
5
Recap What should Processes include?
Activities such as prototyping and incremental delivery to cope with change.
How is Incremental development may be a Plan-Driven Model or Agile Model
As Specification, development and validation are interleaved. May be plan-driven or agile.
What is software design?
Design a software structure that realises the specification
What happens during *Initial* phase
Essentially uncontrolled
What happens during the *Evaluate prototype* in the process of prototype development
Evaluation report
What happens during the *Develop prototype* in the process of prototype development
Executable Prototype
What is the main drawback of the waterfall model
Is the difficulty of accommodating change after the process is underway. In principle, a phase has to be complete before moving onto the next phase.
Although the essence of iterative processes is that the specification is developed in conjunction with the software what do it conflicts with?
It conflicts with the procurement model of many organizations, where the complete system specification is part of the system development contract.
What does change tolerance normally involves
It involves some form of incremental development. Proposed changes may be implemented in increments that have not yet been developed. If this is *possible*, then only a single increment i.e a small part of the system may have be altered to incorporate the change.
What happens during the *Architectural design*
It is Where you identify the overall structure of the system, the principal components, subsystems or modules, their relationships and how they are distributed
What is a Software prototype?
It is an initial version of a system used to demonstrate concepts and try out design options.
Recap What is Software validation
It is the process of checking that the system conforms to its specification and that it meets the real needs of the users of the system.
Recap what are Requirements engineering
It is the process of developing a software specification.
What happens during the *Interface design*
It is where you define the interfaces between system components.
What happens during the *Database design*
It is where you design the system data structures and how these are to be represented in a database.
What happens during the *Component selection and design*
It is where you search for reusable components. If unavailable, you design how it will operate.
What does Process improvement means
It means understanding existing processes and changing these processes to increase product quality and/or reduce costs and development time
Why is that most systems require a set of basic facilities that are used by different parts of the system.
Its due to requirements that are not defined in detail until an increment is to be implemented, it can be hard to identify common facilities that are needed by all increments.
How is the process not visible a problem when using Incremental development?
Managers need regular deliverables to measure progress. If systems are developed quickly, it is not cost-effective to produce documents that reflect every version of the system.
What must we know about The Waterfall model, Integration and configuration and Incremental development in terms of the real world practice
Most large systems are developed using a process that incorporates elements from all of these models.
Give an example of a Number of occurrences of a particular event
Number of defects discovered.
Recap What does the General process models describe
They describe the organization of software processes.
What happens during the *Define prototype functionality* in the process of prototype development
Outline definition
What happens in the *Process change* part of Process improvement activities
Process changes are proposed to address some of the identified process weaknesses. These are introduced and the cycle resumes to collect data about the effectiveness of the changes.
What happens during *Optimizing* phase
Process improvement strategies defined and used
What happens during *Defined* phase
Process management procedures and strategies defined and used
What happens during *Repeatable* phase
Product management procedures defined and used
What happens during the *Establish prototype* in the process of prototype development
Prototype Plan
What must understand about the *Throw-away prototypes* stage?
Prototypes should be discarded after development as they are not a good basis for a production system
What happens during *Managed* phase
Quality management strategies defined and used
What does SEI stand for in software engineering?
Software Engineering Institute
Recap what are Software processes?
Software processes are the activities involved in producing a software system.
What happens during the *System testing* part of the Testing Stage
Testing of the system as a whole. Testing of emergent properties is particularly important.
What happens during the *Customer testing* part of the Testing Stage
Testing with customer data to check that the system meets the customer's needs.
Recap what should understand about structured Processes
That Processes may be structured for iterative development and delivery so that changes may be made without disrupting the system as a whole.
What changes in the Evolution must understand when involved with Software Processes?
That changing the system in response to changing customer needs.
What must understand in about the level of process maturity when using the process maturity approach?
That he level of process maturity reflects the extent to which good technical and management practice has been adopted in organizational software development processes.
What Validation must we check when involved with Software Processes?
That it does what the customer wants
Although it is easier to get customer feedback on the development work that has been done using Incremental development in what why is this easier for Customers?
The Customers can comment on demonstrations of the software and see how much has been implemented.
What does design and implementation have in common
The activities of design and implementation are closely related and may be inter-leaved.
In terms of the cost of accommodating changing customer requirements is reduced using Incremental development what is actually reduced?
The amount of analysis and documentation that has to be redone is much less than is required with the waterfall model.
What happens in the *Process analysis* part of Process improvement activities
The current process is assessed, and process weaknesses and bottlenecks are identified. Process models (sometimes called process maps) that describe the process may be developed.
Although the Process measurements should be used to assess process improvements what should actually the improvement be driven instead measurements
The improvement driver should be the organizational objectives.
Recap what does the SEI process maturity framework identifies
The maturity levels that essentially correspond to the use of good software engineering practice.
What Design and implementation must we define when involved with Software Processes?
The organization of the system and implementing the system
What must understand in about The primary characteristics of agile methods when applying the Agile Approach?
The primary characteristics of agile methods are rapid delivery of functionality and responsiveness to changing customer requirements.
What happens between Software design and implementation?
The process of converting the system specification into an executable system.
What is Software specification?
The process of establishing what services are required and the constraints on the system's operation and development.
How is Integration and configuration may be a Plan-Driven Model or Agile Model
The system is assembled from existing configurable components. May be plan-driven or agile.
Name a Software Process Model that a Plan-Driven model
The waterfall model
Recap what are Software process models
They are abstract representations of these processes.
Recap what is the principal approaches to process improvement?
They are agile approaches, geared to reducing process overheads, and maturity-based approaches based on better process management and the use of good software engineering practice.
Recap what is the Design and implementation processes
They are processes that concerned with transforming a requirements specification into an executable software system.
What are *Plan-Driven Processes*?
They are processes where all of the process activities are planned in advance and progress is measured against this plan.
What are COTS systems
They are sometimes Stand-alone application systems that are based on software reuse where systems are integrated from existing components or application systems
Give an example of a Resource required for processes or activities
Total effort in person-days.
What is Implementation?
Translate this structure into an executable program
How is System structure tending to degrade as new increments are added a problem when using Incremental development?
Unless time and money is spent on refactoring to improve the software, regular change tends to corrupt its structure. Incorporating further software changes becomes increasingly difficult and costly.
What does V & V stand for in Software Engineering?
Verification and validation
Recap when does Software evolution takes place
When you change existing software systems to meet new requirements. The software must evolve to remain useful.
What happens in the *Process measurement* part of Process improvement activities
You measure one or more attributes of the software process or product. These measurements forms a baseline that helps you decide if process improvements have been effective.
Give an example of the Change anticipation?
a prototype system may be developed to show some key features of the system to customers.
Although quantitative process data should be collected wherever possible however in practice what actually happens?
organizations do not have clearly defined process standards this is very difficult as you don't know what to measure. A process may have to be defined before any measurement is possible.
What happens in *agile Processes*?
planning is incremental and it is easier to change the process to reflect changing customer requirements.
What Specification must we define when involved with Software Processes?
what the system should do
