CHAPTER 1 - Software and Software Engineering

Software

Instructions (computer programs) that when executed provide desired features, function, and performance

Software

Data structures that enable the programs to adequately manipulate information

Software

Documentation that describes the operation and use of the programs.

Software

Is developed or engineered, it is not manufactured in the classical sense.

Software

doesn't "wear out."

Custom-built

Although the industry is moving toward component-based construction, most software continues to be custom-built.

Open World Computing

new category of software. pervasive, distributed computing

Ubiquitous Computing

new category of software. wireless networks

Netsourcing

new category of software. the Web as a computing engine

Open Source

new category of software. "free" source code open to the computing community (a blessing, but also a potential curse!)

Adapted

Software must be _______ to meet the needs of new computing environments or technology.

Enhanced

Software must be ________ to implement new business requirements.

Extended to make it interoperable

Software must be ________ __ ____ __ _____________ with other more modern systems or databases.

re-architected

Software must be __-___________ to make it viable within a network environment.

Network Intensiveness

characteristic of webapps. A WebApp resides on a network and must serve the needs of a diverse community of clients.

Concurrency

characteristic of webapps. A large number of users may access the WebApp at one time.

Unpredictable Load

characteristic of webapps. The number of users of the WebApp may vary by orders of magnitude from day to day.

Performance

characteristic of webapps. If a WebApp user must wait too long (for access, for server-side processing, for client-side formatting and display), he or she may decide to go elsewhere.

Availability

characteristic of webapps. Although expectation of 100 percent availability is unreasonable, users of popular WebApps often demand access on a "24/7/365" basis.

Data Driven

characteristic of webapps. The primary function of many WebApps is to use hypermedia to present text, graphics, audio, and video content to the end-user.

Content Sensitive

characteristic of webapps. The quality and aesthetic nature of content remains an important determinant of the quality of a WebApp.

Continuous Evolution

characteristic of webapps. Unlike conventional application software that evolves over a series of planned, chronologically-spaced releases, Web applications evolve continuously.

Immediacy

characteristic of webapps. Although immediacy—the compelling need to get software to market quickly—is a characteristic of many application domains, WebApps often exhibit a time to market that can be a matter of a few days or weeks.

Security

characteristic of webapps. Because WebApps are available via network access, it is difficult, if not impossible, to limit the population of end users who may access the application.

Aesthetics

characteristic of webapps. An undeniable part of the appeal of a WebApp is its look and feel.

Software Engineering

the establishment and use of sound engineering principles in order to obtain economically software that is reliable and works efficiently on real machines.

Software Engineering

(1) The application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software: that is, the application of engineering to software.

○ The study of approaches as in (1).

Quality focus, process model, methods, tools

4 layers of a layered technology in software engineering (bottom up)

Work tasks, work products, milestones and deliverables, qa checkpoints

4 framework activities under the process framework

Communication, planning, modelling, construction, deployment

5 parts of framework activities

Umbrella Activities

these bulletpoints refer to what?

• Software Project Management

• Formal Technical Reviews

• Software Quality Assurance

• Software Configuration Management

• Work Product Preparation and Production

• Reusability Management

• Measurement

• Risk Management

Understand the problem, plan a solution, carry out the plan, examine the result for accuracy

4 steps of the essence of practice according to George Polya

George Polya

father of modern problem solving

Stakeholders

Who has a stake in the solution to the problem? That is, who are the ____________?

Data, functions, features

What are the unknowns? What ____, _________, and ________ are required to properly solve the problem?

Smaller

Can the problem be compartmentalized? − Is it possible to represent _______ problems that may be easier to understand?

Analysis model

Can the problem be represented graphically? − Can an ________ _____ be created?

Patterns

Have you seen similar problems before? − Are there ________ that are recognizable in a potential solution? Is there existing software that implements the data, functions, and features that are required?

Reusable

Has a similar problem been solved? − If so, are elements of the solution ________?

solutions

Can subproblems be defined? − If so, are _________ readily apparent for the subproblems?

design model

Can you represent a solution in a manner that leads to effective implementation? − Can a ______ _____ be created?

traceable

Does the solution conform to the plan? − Is source code _________ to the design model?

correctness proofs

Is each component part of the solution provably correct? − Has the design and code been reviewed, or better, have ___________ ______ been applied to algorithm?

testing strategy

Is it possible to test each component part of the solution? − Has a reasonable _______ ________ been implemented?

validated

Does the solution produce results that conform to the data, functions, and features that are required? − Has the software been _________ against all stakeholder requirements?

The Reason It All Exists, KISS, Maintain the Vision, What You Produce Others Will Consume, Be Open to the Future, Plan Ahead for Reuse Think!

7 hooker's general principles

business

Every software project is precipitated by some ________ need— − The need to correct a defect in an existing application− The need to the need to adapt a 'legacy system' to a changing business environment− The need to extend the functions and features of an existing application, or − The need to create a new product, service, or system.