Software development: Difference between revisions

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{{EngvarB|date=December 2021}}

{{Software development process}}

'''Software development''' is the process of [[designing]] and [[Implementation|implementing]] a [[software]] solution to [[Computer user satisfaction|satisfy]] a [[User (computing)|user]]. The process is more encompassing than [[Computer programming|programming]], writing [[source code|code]], in that it includes conceiving the goal, evaluating feasibility, analyzing [[software requirements|requirements]], [[software design|design]], [[software testing|testing]] and [[software release life cycle|release]]. The process is part of [[software engineering]] which also includes [[management|organizational management]], [[Software project management|project management]], [[configuration management]] and other aspects.{{sfn|Dooley|2017|p=1}}

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Software development involves many [[software tools|tools]] including: [[compiler]], [[integrated development environment]] (IDE), [[version control]], [[computer-aided software engineering]], and [[word processor]].

The details of the process used for a development effort variesvary. The process may be confined to a formal, documented [[Standards (software)|standard]], or it can be customized and [[Emergence|emergent]] for the development effort. The process may be sequential, in which each major phase (i.e., design, implement, and test) is completed before the next begins, but an iterative approach {{endash}}– where small aspects are separately designed, implemented, and tested {{endash}}– can reduce risk and cost and increase quality.

==Methodologies==

{{main|Software development methodology}}

[[File:Evolutionary prototyping model.jpg|thumb|upright=1.5|Flowchart of the [[evolutionary prototyping model]], an [[iterative]] development model{{sfn|Dooley|2017|p=12}}]]

Each of the available methodologies areis best suited to specific kinds of projects, based on various technical, organizational, project, and team considerations.<ref>System Development Methodologies for Web-Enabled E-Business: A Customization Framework

Linda V. Knight (DePaul University, USA), Theresa A. Steinbach (DePaul University, USA), and Vince Kellen (Blue Wolf, USA)</ref>

*The simplest methodology is the "code and fix", typically used by a single programmer working on a small project. After briefly considering the purpose of the program, the programmer codes it and runs it to see if it works. When they are done, the product is released. This methodology is useful for prototypes but cannot be used for more elaborate programs.{{sfn|Dooley|2017|pp=8-9}}

*In the top-down [[waterfall model]], feasibility, analysis, [[software design|design]], development, [[Software quality assurance|quality assurance]], and implementation occur sequentially in that order. This model requires one step to be complete before the next begins, causing delays, and makes it impossible to revise previous steps if necessary.{{sfn|Dooley|2017|p=9}}{{sfn|Langer|2016|pp=2-3, 5–6}}{{sfn|Tucker |Morelli |de Silva |2011|p=8}}

*With [[iterative]] processes these steps are interleaved with each other for improved flexibility, efficiency, and more realistic scheduling. Instead of completing the project all at once, one might go through most of the steps with one component at a time. [[Iterative and incremental development|Iterative development]] also lets developers prioritize the most important features, enabling lower priority ones to be dropped later on if necessary.{{sfn|Langer|2016|pp=2-3, 5–6}}{{sfn|Dooley|2017|p=11}} [[agile software development|Agile]] is one popular method, originally intended for small or medium sized projects, that focuses on giving developers more control over the features that they work on to reduce the risk of time or cost overruns.{{sfn|Dooley|2017|p=13}} Derivatives of agile include [[extreme programming]] and [[Scrum (software development)|Scrum]].{{sfn|Dooley|2017|p=13}} [[Open-source software development]] typically uses agile methodology with concurrent design, coding, and testing, due to reliance on a distributed network of volunteer contributors.{{sfn|Tucker |Morelli |de Silva |2011|pp=41-42}}

*Beyond agile, some companies integrate [[information technology]] (IT) operations with software development, which is called [[DevOps]] or [[DevSecOps]] including [[computer security]].{{sfn|Vishnu|2019|pp=1-2}} DevOps includes continuous development, [[continuous testing|testing]], [[continuous integration|integration]] of new code in the version control system, [[continuous deployment|deployment]] of the new code, and sometimes [[continuous delivery|delivery]] of the code to clients.<ref>{{Cite journal |last=Laukkanen |first=Eero |last2=Itkonen |first2=Juha |last3=Lassenius |first3=Casper |date=2017 |title=Problems, causes and solutions when adopting continuous delivery—A systematic literature review |journal=Information and Software Technology |volume=82 |pages=55–79 |doi=10.1016/j.infsof.2016.10.001|doi-access=free }}</ref> The purpose of this integration is to deliver IT services more quickly and efficiently.{{sfn|Vishnu|2019|pp=1-2}}

Another focus in many programming methodologies is the idea of trying to catch issues such as [[security vulnerabilities]] and [[Bug (computer programming)|bugs]] as early as possible ([[shift-left testing]]) to reduce the cost of tracking and fixing them.{{sfn|Winters|Manshreck|Wright |2020|p=17}}

In 2009, it was estimated that 32 percent% of software projects were delivered on time and on budget, and with the full functionality. An additional 44 percent% were delivered, but were missing at least one of thesetheir features. The remaining 24 percent% were cancelled prior tobefore release.{{sfn|Tucker |Morelli |de Silva |2011|p=6}}

==Steps==

[[Software development life cycle]] refers to the systematic process of developing [[application software|applications]].{{sfn|Saif|2019|pp=46–47}}

===Feasibility===

The sources of ideas for software products are plentiful. These ideas can come from [[market research]], including the [[demographics]] of potential new customers, existing customers, sales prospects who rejected the product, other internal software development staff, or a creative third party. Ideas for software products are usually first evaluated by [[marketing]] personnel for economic feasibility, fit with existing channels of distribution, possible effects on existing product lines, required [[Software feature|features]], and fit with the company's marketing objectives. In the marketing evaluation phase, the cost and time assumptions becomeare evaluated.{{sfn|Morris|2001|p=1.10}} The feasibility analysis estimates the project's [[return on investment]], its development cost and timeframe. Based on this analysis, the company can make a business decision to invest in further development.{{sfn|Langer|2016|p=7}} After deciding to develop the software, the company is focused on delivering the product at or below the estimated cost and time, and with a high standard of quality (i.e., lack of bugs) and the desired functionality. Nevertheless, most software projects run late, and sometimes compromises are made in features or quality to meet a deadline.{{sfn|Dooley|2017|pp=3, 8}}

===Analysis===

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===Design===

{{main|software design}}

Design involves choices about the implementation of the software, such as which [[programming language]]s and database software to use, or how the hardware and network communications will be organized. Design may be iterative with users consulted about their needs in a process of [[trial and error]]. Design often involves people who are expert in aspectaspects such as [[database design]], screen architecture, and the performance of servers and other hardware.{{sfn|Langer|2016|p=8}} Designers often attempt to find [[software design patterns|patterns]] in the software's functionality to spin off distinct modules that can be reused with [[object-oriented programming]]. An example of this is the [[model–view–controller]], an interface between a [[graphical user interface]] and the [[Frontend and backend|backend]].{{sfn|Dooley|2017|p=142}}

===Programming===

{{main|computer programming}}

The central feature of software development is creating and understanding the software that implements the desired functionality.{{sfn|Tucker |Morelli |de Silva |2011|p=31}} There are various strategies for writing the code. Cohesive software has various components that are independent from each other.{{sfn|Langer|2016|p=8}} Coupling is the interrelation of different software components, which is viewed as undesirable because it increases the difficulty of [[Software maintenance|maintenance]].{{sfn|Langer|2016|pp=8–9}} Often, software programmers do not follow industry best practices, resulting in code that is inefficient, difficult to understand, or lacking [[software documentation|documentation]] on its functionality.{{sfn|Tucker |Morelli |de Silva |2011|pp=31-32}} These standards are especially likely to break down in the presence of deadlines.{{sfn|Tucker |Morelli |de Silva |2011|pp=34-35}} As a result, testing, debugging, and revising the code becomesbecome much more difficult. [[Code refactoring]], for example, adding more comments to the code, is a solution to improve the understandability of the code.{{sfn|Tucker |Morelli |de Silva |2011|pp=31-32, 35}}

===Testing===

{{main|software testing}}

Testing is the process of ensuring that the code executes correctly and without errors. [[Debugging]] is performed by each software developer on their own code to confirm that the code does what it is intended to. In particular, it is crucial that the software executes on all inputs, even if the result is incorrect.{{sfn|Langer|2016|p=9}} [[Code review]]s by other developers are often used to scrutinize new code added to the project, and according to some estimates dramatically reduce the number of bugs persisting after testing is complete.{{sfn|Dooley|2017|p=272}} Once the code has been submitted, [[quality assurance]]—a – a separate department of non-programmers for most large companies—testcompanies – test the accuracy of the entire software product. [[Acceptance tests]] derived from the original software requirements are a popular tool for this.{{sfn|Langer|2016|p=9}} Quality testing also often includes stress and load checking (whether the software is robust to heavy levels of input or usage), [[integration testing]] (to ensure that the software is adequately integrated with other software), and [[compatibility testing]] (measuring the software's performance across different operating systems or browsers).{{sfn|Langer|2016|p=9}} When tests are written before the code, this is called [[test-driven development]].{{sfn|Tucker |Morelli |de Silva |2011|p=9}}

===Production===

{{see also|Software release life cycle}}

Production is the phase in which software is deployed to the end user.{{sfn|Langer|2016|p=10}} During production, the developer may create technical support resources for users{{sfn|Tucker |Morelli |de Silva |2011|p=37}}{{sfn|Langer|2016|p=10}} or a process for fixing bugs and errors that were not caught earlier. There might also be a return to earlier development phases if user needs changed or were misunderstood.{{sfn|Langer|2016|p=10}}

==Workers==

Software development is performed by '''software developers''', usually working on a team. Efficient communications between team members is essential to success. This is more easily achieved if the team is small, used to working together, and located near each other.{{sfn|Dooley|2017|p=2}} Communications also help identify problems at an earlier statestage of development and avoid duplicated effort. Many development projects avoid the risk of losing essential knowledge held by only one employee by ensuring that multiple workers are familiar with each component.{{sfn|Winters|Manshreck|Wright |2020|pp=30–31}} Software development involves professionals from various fields, not just software [[Programmer|programmers]] but also product managers who set the strategy and roadmap for the product,<ref>{{Cite web |date=2025-01-21 |title=What Does a Product Manager Do? And How to Become One |url=https://www.coursera.org/articles/what-does-a-product-manager-do |access-date=2025-05-05 |website=Coursera |language=en}}</ref> individuals specialized in testing, documentation writing, [[graphic design]], user support, [[marketing]], and fundraising. Although workers for proprietary software are paid, most contributors to [[open-source software]] are volunteers.{{sfn|Tucker |Morelli |de Silva |2011|p=7}} Alternately, they may be paid by companies whose [[business model]] does not involve selling the software, but something else—suchelse – such as services and modifications to open source software.{{sfn|Tucker |Morelli |de Silva |2011|pp=14-15}}

==Models and tools==

===Computer-aided software engineering===

[[Computer-aided software engineering]] (CASE) is tools for the partial [[automation]] of software development.{{sfn|Langer|2016|p=22}} CASE enables designers to sketch out the logic of a program, whether one to be written, or an already existing one to help integrate it with new code or [[reverse engineer]] it (for example, to change the [[programming language]]).{{sfn|Langer|2016|pp=108-110108–110, 206}}

===Documentation===

{{main|Software documentation}}

Documentation comes in two forms that are usually kept separate—thatseparate – one intended for software developers, and thatanother made available to the end user to help them use the software.{{sfn|Tucker |Morelli |de Silva |2011|p=243}}{{sfn|Winters|Manshreck|Wright |2020|p=192}} Most developer documentation is in the form of [[code comment]]s for each file, [[class (programming)|class]], and [[method (programming)|method]] that cover the [[application programming interface]] (API)—how the piece of software can be accessed by another—and often implementation details.{{sfn|Winters|Manshreck|Wright |2020|pp=193–195}} This documentation is helpful for new developers to understand the project when they begin working on it.{{sfn|Tucker |Morelli |de Silva |2011|p=143}} In agile development, the documentation is often written at the same time as the code.{{sfn|Tucker |Morelli |de Silva |2011|p=144}} User documentation is more frequently written by [[technical writing|technical writers]].{{sfn|Winters|Manshreck|Wright |2020|p=204}}

===Effort estimation===

{{main|Software development effort estimation}}

Accurate estimation is crucial at the feasibility stage and in delivering the product on time and within budget. The process of generating estimations is often delegated by the [[Software project management|project manager]].{{sfn|Saif|2019|pp=50–51}} Because the effort estimation is directly related to the size of the complete application, it is strongly influenced by the addition of features in the requirements—the more requirements, the higher the development cost. Aspects not related to functionality, such as the experience of the software developers and code reusability, are also essential to consider in estimation.{{sfn|Saif|2019|pp=52–53}} {{as of|2019}}, most of the tools for estimating the amount of time and resources for software development were designed for conventional applications and are not applicable to [[web application]]s or [[mobile application]]s.{{sfn|Saif|2019|p=45}}

===Integrated development environment===

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{{main|Version control}}

Version control is a popular way of managing changes made to the software. Whenever a new version is checked in, the software saves a [[backup]] of all modified files. If multiple programmers are working on the software simultaneously, it manages the merging of their code changes. The software highlights cases where there is a conflict between two sets of changes and allows programmers to fix the conflict.{{sfn|Dooley|2017|pp=246–247}}

===View model===

[[File:TEAF Matrix of Views and Perspectives.svg|thumb|The [[TEAF]] Matrix of Views and Perspectives]]

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The purpose of viewpoints and views is to enable human engineers to comprehend very [[complex system]]s and to organize the elements of the problem around domains of [[expertise]]. In the [[engineering]] of physically intensive systems, viewpoints often correspond to capabilities and responsibilities within the engineering organization.<ref name="NIST2003">Edward J. Barkmeyer ea (2003). [http://www.mel.nist.gov/msidlibrary/doc/AMIS-Concepts.pdf ''Concepts for Automating Systems Integration''] {{Webarchive|url=https://web.archive.org/web/20170125115826/http://www.mel.nist.gov/msidlibrary/doc/AMIS-Concepts.pdf |date=25 January 2017 }} NIST 2003.</ref>

=== Fitness functions ===

[[Fitness function|Fitness functions]] are automated and objective tests to ensure that the new developments don't deviate from the established constraints, checks and compliance controls.<ref>{{Cite book |title=Fundamentals of Software Architecture: An Engineering Approach |publisher=O'Reilly Media |year=2020 |isbn=978-1492043454}}</ref>

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==References==

{{reflist}}

==Further reading==

{{refbegin|30em|indent=yes}}

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*{{Cite book |last=Morris |first=Joseph M. |title=Software industry accounting |date=2001 |publisher=[[John Wiley & Sons]] |edition=2nd |oclc=53863959}}

*{{Cite book |last=Rittinghouse |first=John |title=Managing Software Deliverables: A Software Development Management Methodology |publisher=Digital Press |year=2003 |isbn=155558313X}}

*{{Cite book |last=Saif |first=Syed Mohsin |title=Tools and Techniques for Software Development in Large Organizations: Emerging Research and Opportunities: Emerging Research and Opportunities |date=2019 |publisher=[[IGI Global]] |isbn=978-1-7998-1865-6 |editor-last=Vishnu |editor-first=Pendyala |pages=45–97 |language=en |chapter=Software Effort Estimation for Successful Software Application Development}}

*{{Cite book |last=Tucker |first=Allen |title=Software Development: An Open Source Approach |last2=Morelli |first2=Ralph |last3=de Silva |first3=Chamindra |date=2011 |publisher=CRC Press |isbn=978-1-4398-8460-7 |language=en}}

*{{Cite book |last=Vishnu |first=Pendyala |title=Tools and Techniques for Software Development in Large Organizations: Emerging Research and Opportunities: Emerging Research and Opportunities |date=2019 |publisher=IGI Global |isbn=978-1-7998-1865-6 |editor-last=Vishnu |editor-first=Pendyala |pages=1–20 |language=en |chapter=Evolution of Integration, Build, Test, and Release Engineering Into DevOps and to DevSecOps}}