Chapter 2 Software Engineering
Overview
Software engineering encompasses a process, a collection of methods, and
an array of tools that allow professionals to build high quality software.
Software engineers view computer software, as being made up of the
programs, documents, and data required to design and build the system.
Software users are only concerned with whether or not software products
meet their expectations and make their tasks easier to complete.
Software Engineering Realities
Problem should be understood before software solution is developed
Design is a pivotal activity
Software should exhibit high quality
Software should be maintainable
Software Engineering
Software engineering is the establishment of sound engineering principles in
order to obtain reliable and efficient software in an economical manner.
Software engineering is the application of a systematic, disciplined,
quantifiable approach to the development, operation, and maintenance of
software.
Software engineering encompasses a process, management techniques,
technical methods, and the use of tools.
Generic Software Process Framework
Communication (customer collaboration and requirement gathering)
Planning (establishes engineering work plan, describes technical risks, lists
resources required, work products produced, and defines work schedule)
Modeling (creation of models to help developers and customers understand
the requires and software design)
Construction (code generation and testing)
Deployment (software delivered for customer evaluation and feedback)
Software Engineering Umbrella Activities
Software project tracking and control (allows team to assess progress and
take corrective action to maintain schedule)
Risk management (assess risks that may affect project outcomes or quality)
Software quality assurance (activities required to maintain software quality)
Technical reviews (assess engineering work products to uncover and remove
errors before they propagate to next activity)
Measurement (define and collect process, project, and product measures to
assist team in delivering software meeting customer needs)
Software configuration management (manage effects of change)
Reusability management (defines criteria for work product reuse and
establish mechanisms to achieve component reuse)
Work product preparation and production (activities to create models,
documents, logs, forms, lists, etc.)
Attributes for Comparing Process Models
Overall flow and level of interdependencies among tasks
Degree to which work tasks are defined within each framework activity
Degree to which work products are identified and required
Manner in which quality assurance activities are applied
Manner in which project tracking and control activities are applied
Overall degree of detail and rigor of process description
Degree to which stakeholders are involved in the project
Level of autonomy given to project team
Degree to which team organization and roles are prescribed
Essence of Practice
Understand the problem (communication and analysis)
Plan a solution (software design)
Carry out the plan (code generation)
Examine the result for accuracy (testing and quality assurance)
Understand the Problem
Who are the stakeholders?
What functions and features are required to solve the problem?
Is it possible to create smaller problems that are easier to understand?
Can a graphic analysis model be created?
Plan the Solution
Have you seen similar problems before?
Has a similar problem been solved?
Can readily solvable subproblems be defined?
Can a design model be created?
Carry Out the Plan
Does solution conform to the plan?
Is each solution component provably correct?
Examine the Result
Is it possible to test each component part of the solution?
Does the solution produce results that conform to the data, functions, and
features required?
Software Practice Core Principles
1.
2.
3.
4.
Software exists to provide value to its users
Keep it simple stupid (KISS)
Clear vision is essential to the success of any software project
Always specify, design, and implement knowing that someone else will have
to understand what you have done to carry out his or her tasks
5. Be open to future changes, dont code yourself into a corner
6. Planning ahead for reuse reduces the cost and increases the value of both
the reusable components and the systems that require them
7. Placing clear complete thought before any action almost always produces
better results
Software Creation
Almost every software project is precipitated by a business need (e.g. correct
a system defect, adapt system to changing environment, extend existing
system, create new system)
Many times an engineering effort will only succeed if the software created for
the project succeeds
The market will only accept a product is the software embedded within it
meets the customers stated or unstated needs
