Understanding Software Engineering Principles

• Software consists of programs, data, and documentation, each with its configurations
• Software engineering involves technologies, methods, and tools based on engineering principles used in software development
• A core objective of software engineering is to provide a structure for developing high-quality software

What Is It?

• Software is what software professionals build and support long-term.
• It includes instructions (computer programs), which provide features, functions, and performance during code execution.
• Data structures let programs store and manipulate data.
• Documentation describes how the program works and is used.

Dual Role

• Software serves as a product.
• It delivers computing potential.
• It produces, manages, obtains, alters, shows, or sends out data.
• Software acts as a vehicle for product delivery.
• It directly supports system functionality.
• It controls other programs like operating systems.
• It influences communication through networking software.
• It facilitates the creation of other software through tools.

Products

• Generic products are independent and available to any customer.
• Examples include PC software for editing, graphics, project management tools, CAD software, and appointment systems for specific markets like dentists.
• Customized products are made to order for a specific client.
• Examples are embedded control systems, air traffic control software, and traffic monitoring systems.

Features

• Software is engineered or developed, not manufactured, which avoids the quality issues of traditional manufacturing.
• It does not wear out like hardware but can degrade.
• The industry shifts toward component-based software, most software remains custom-built.

Costs

• Software costs often exceed hardware costs
• Software maintenance costs surpass development costs, particularly in long-lived systems.
• Software engineering seeks cost-effective software development and is more expensive.

Cost of Change

• Definition is 1x more expensive
• Development is 1.5 - 6x more expensive
• After release 60 - 100x more expensive

Software Applications Categorize

• System software includes compilers, editors, and file management tools.
• Application software is stand-alone programs for specific needs.
• Engineering/scientific software is characterized by heavy use of algorithms.
• Embedded software resides within a product or system.
• Product-line software offers specific capabilities for diverse users.
• Web Apps network-centric software.
• AI software uses non-numerical algorithms for complex problem-solving.

New Categories

• Open world computing enables pervasive, ubiquitous, distributed computing with wireless networks.
• Net sourcing uses the Web as a computing engine.
• Open source provides "free" source code to the computing community. Data mining, grid computing, cognitive machines and software for nanotechnologies are also included

Legacy Software

• It must change to adapt to new computing environments and technologies.
• It needs to implement new business requirements.
• There is a need to expand to interface with modern systems and databases.
• It is necessary to re-architect to survive in a networked environment.

Characteristics of Web Apps

• It sits on a network and serves various client communities
• Many users can access at once
• The amount of users can vary greatly each day
• Users will leave if access is too slow
• Users demand constant access
• Many WebApps use hypermedia for text, graphics, audio, or video
• Quality of content matters as do aesthetics
• Conventional applications evolve over time
• WebApps must get software to market fast
• Difficult to restrict who can use the application
• The look and feel of a WebApp matters

IEEE Definition

• Software engineering includes a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software.
• It also examines methods for the systematic, disciplined, and quantifiable development, operation, and maintenance of software.

Attributes

• Good software should be easy to change to meet customer needs and to correct when needed.
• It should include reliability, security, and safety features to prevent errors and protect data.
• Software should use system resources efficiently.
• It must be understandable, usable, and work with all other systems.

Ethical Responsibility

• It involves responsibilities beyond technical skills.
• They must behave honestly and ethically
• Ethical behavior involves professional accountability

Definition

• Software engineering emphasizes quality
• It consists of a process model, methods, and tools.
• The process model offers a framework
• The methods give specific tactics
• The tolls support and speed up processes and methods

Process

• Its a collection of activities to create one product
• No one version of software development, constantly being updated
• Aimed at helping those involved to pick what best suites their needs
• Aims at delivering software with good quality in the time restraints

Framework

• The framework serves to manages and builds software
• Consists of a work tasks, work products, milestones and deliverables and QA checkpoints

5 Activities

• Communication to understand the clients goals
• Programing to define the project needs and work products
• Modelling to sketch how the architecturally the system looks
• Creation to create the code and test it
• Deployment to get to the customer so they can use it and give feedback
• These 5 steps can be applied to many projects
• Applied over and over with projects
• With each iteration, builds upon previous version

Umbrella

• Complements the 5 framework activities and management of team and project
• Includes program assessment for quality and risks
• Technical reviews and collects project and product aspects
• Manage the effects of changing software
• Make reusable components that are created out models, etc

Adapting a Process Model

• The process has to be flexible to changing needs
• Can be different from project to project
• The differences are in activities, definitions of phases, work products, how to control quality, how strict the process is

Process Models

• Focuses on a definition with the goal of improving quality and manageable project
• Also can be high, with a large degree of bureaucracy.
• Agile promotes flexibility with web applications
• They are based on a series of rules that lead to less emphasis on process.

Prescriptive or Agile?

• Prescriptive includes documentation and has a planned process
• Agile is less formal with teams
• Prespective has clear control when in a team environment
• Agile can be hard to scale
• Prespective is good for large or dangerous items
• Agile is small, easy to manage

1 - Understanding

• Figure out who the stakeholders are
• What do the stakeholders want and how can that objective get met
• Do you already know which functions are needed
• Can the function break down into parts
• Does the data exist
• Is the item easy to handle

2 - Solution

• Have similar problems been seen before
• Were there similar problems solved
• Can sub issues define solutions
• Can a solution be efficiently implemented

3 - Plan

• Is their code readable
• If the product has been tested
• If the solution helps the user reach their goal
• Is there a similar solution already

Principles:

• Why is it there
• Keep It Simple, Stupid
• Maintain the Vision
• What You Produce, Others Will Consume
• Open to the Future
• Plan Ahead for Reuse
• Think before you do

Software Myths

• Erroneous beliefs about the product
• Easy to build or add to
• Believing in a myth will lead to bad choices
• It is important to be grounded in reality
• If you have problems, just add more developers

Some myths

• Once it is running, job is done, not the whole 80%
• Assessing its quality must be assessed during testing
• Software will take too long, better to have less and get a quality output for less