What is Software Engineering?

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Software engineering

Software engineering is the application of engineering to the design, development, implementation and maintenance of software in a systematic method.[1][2][3]

Typical formal definitions of software engineering are:

"research, design, develop, and test operating systems-level software, compilers, and network distribution software for medical, industrial, military, communications, aerospace, business, scientific, and general computing applications."[4]

"the systematic application of scientific and technological knowledge, methods, and experience to the design, implementation, testing, and documentation of software";[5]

"the application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software";[6]

"an engineering discipline that is concerned with all aspects of software production";[7]

and "the establishment and use of sound engineering principles in order to economically obtain software that is reliable and works efficiently on real machines."[8]

Contents

1 History
2 Subdisciplines
3 Education
4 Profession
4.1 Employment
4.2 Certification
4.3 Impact of globalization
5 Related fields
6 Controversy
6.1 Over definition
6.2 Criticism
7 See also
8 Notes
9 References
10 Further reading
11 External links

History

When the first digital computers appeared in the early 1940s,[10] the instructions to make them operate were wired into the machine. Practitioners quickly realized that this design was not flexible and came up with the "stored program architecture" or von Neumann architecture. Thus the division between "hardware" and "software" began with abstraction being used to deal with the complexity of computing.

Programming languages started to appear in the 1950s and this was also another major step in abstraction. Major languages such as Fortran, ALGOL, and COBOL were released in the late 1950s to deal with scientific, algorithmic, and business problems respectively. Edsger W. Dijkstra wrote his seminal paper, "Go To Statement Considered Harmful",[11] in 1968 and David Parnas introduced the key concept of modularity and information hiding in 1972[12] to help programmers deal with the ever increasing complexity of software systems.

The term "software engineering", coined first by Anthony Oettinger[9] and then used by Margaret Hamilton,[13][14] was used in 1968 as a title for the world's first conference on software engineering, sponsored and facilitated by NATO. The conference was attended by international experts on software who agreed on defining best practices for software grounded in the application of engineering. The result of the conference is a report that defines how software should be developed. The original report is publicly available.[15]

The discipline of software engineering was created to address poor quality of software, get projects exceeding time and budget under control, and ensure that software is built systematically, rigorously, measurably, on time, on budget, and within specification.[16] Engineering already addresses all these issues, hence the same principles used in engineering can be applied to software. The widespread lack of best practices for software at the time was perceived as a "software crisis".[17][18][19]

Barry W. Boehm documented several key advances to the field in his 1981 book, 'Software Engineering Economics'.[20] These include his Constructive Cost Model (COCOMO), which relates software development effort for a program, in man-years T, to source lines of code (SLOC).  T = k * (SLOC)^{(1+x)} The book analyzes sixty-three software projects and concludes the cost of fixing errors escalates as the project moves toward field use. The book also asserts that the key driver of software cost is the capability of the software development team.

In 1984, the Software Engineering Institute (SEI) was established as a federally funded research and development center headquartered on the campus of Carnegie Mellon University in Pittsburgh, Pennsylvania, United States. Watts Humphrey founded the SEI Software Process Program, aimed at understanding and managing the software engineering process. His 1989 book, Managing the Software Process,[21] asserts that the Software Development Process can and should be controlled, measured, and improved. The Process Maturity Levels introduced would become the Capability Maturity Model Integration for Development(CMMi-DEV), which has defined how the US Government evaluates the abilities of a software development team.

Modern, generally accepted best-practices for software engineering have been collected by the ISO/IEC JTC 1/SC 7 subcommittee and published as the Software Engineering Body of Knowledge (SWEBOK).[22]

Subdisciplines

Software engineering can be divided into thirteen sub-disciplines. They are:[1]

Requirements engineering: The elicitation, analysis, specification, and validation of requirements for software.

Embedded software: The computer software, written to control machines or devices that are not typically thought of as computers. It is typically specialized for the particular hardware that it runs on and has time and memory constraints.

Site Reliability Engineering: The process of managing large scale distributed systems in which software engineering disciplines are employed in an operations environment.

Software design: The process of defining the architecture, components, interfaces, and other characteristics of a system or component. It is also defined as the result of that process.

Software construction: The detailed creation of working, meaningful software through a combination of coding,verification, unit testing, integration testing, and debugging.

Software testing: An empirical, technical investigation conducted to provide stakeholders with information about the quality of the product or service under test.

Software maintenance: The totality of activities required to provide cost-effective support to software.

Software configuration management: The identification of the configuration of a system at distinct points in time for the purpose of systematically controlling changes to the configuration, and maintaining the integrity and traceability of the configuration throughout the system life cycle.

Software engineering management: The application of management activities—planning, coordinating, measuring, monitoring, controlling, and reporting—to ensure that the development and maintenance of software is systematic, disciplined, and quantified.

Software engineering process: The definition, implementation, assessment, measurement, management, change, and improvement of the software life cycle process itself.

Software engineering tools and methods: The computer-based tools that are intended to assist the software life cycle processes (see Computer-aided software engineering) and the methods which impose structure on the software engineering activity with the goal of making the activity systematic and ultimately more likely to be successful.

Software quality management: The degree to which a set of inherent characteristics fulfills requirements.

Software evolution: The process of developing software initially, then repeatedly updating it for various reasons.

Software durability: The solution ability of serviceability of software and to meet user’s needs for a relatively long time.

Software trustworthiness: Trustworthiness would deliver a complete assurance that it will execute its required functions under all probable situations.

Software dependability: The solution ability of serviceability of software that can defensibly be trusted.

Software usability: Usability is a degree of software to perform prescribed a specific task.

Education

Knowledge of computer programming is a prerequisite to becoming a software engineer. In 2004 the IEEE Computer Society produced the SWEBOK, which has been published as ISO/IEC Technical Report 1979:2004, describing the body of knowledge that they recommend to be mastered by a graduate software engineer with four years of experience.[23] Many software engineers enter the profession by obtaining a university degree or training at a vocational school. One standard international curriculum for undergraduate software engineering degrees was defined by the CCSE, and updated in 2004.[24] A number of universities have Software Engineering degree programs; as of 2010, there were 244 Campus Bachelor of Software Engineering programs, 70 Online programs, 230 Masters-level programs, 41 Doctorate-level programs, and 69 Certificate-level programs in the United States.[25]

For practitioners who wish to become proficient and recognized as professional software engineers, the IEEE offers two certifications that extend knowledge above level achieved by an academic degree: Certified Software Development Associate and Certified Software Development Professional.

In addition to university education, many companies sponsor internships for students wishing to pursue careers in information technology. These internships can introduce the student to interesting real-world tasks that typical software engineers encounter every day. Similar experience can be gained through military service in software engineering.

Profession

Legal requirements for the licensing or certification of professional software engineers vary around the world. In the UK, the British Computer Society licenses software engineers and members of the society can also become Chartered Engineers (CEng), while in some areas of Canada, such as Alberta, British Columbia, Ontario,[26] and Quebec, software engineers can hold the Professional Engineer (P.Eng) designation and/or the Information Systems Professional (I.S.P.) designation. In Canada, there is a legal requirement to have P.Eng when one wants to use the title "engineer" or practice "software engineering".

The United States, starting from 2013 offers an NCEES Professional Engineer exam for Software Engineering, thereby allowing Software Engineers to be licensed and recognized.[27] Mandatory licensing is currently still largely debated, and perceived as controversial. In some parts of the US such as Texas, the use of the term Engineer is regulated by law and reserved only for use by individuals who have a Professional Engineer license. The IEEE informs the professional engineer license is not required unless the individual would work for public where health of others could be at risk if the engineer was not fully qualified to required standards by the particular state. Professional engineer licenses are specific to the state which has awarded them, and have to be regularly retaken.

The IEEE Computer Society and the ACM, the two main US-based professional organizations of software engineering, publish guides to the profession of software engineering. The IEEE's Guide to the Software Engineering Body of Knowledge - 2004 Version, or SWEBOK, defines the field and describes the knowledge the IEEE expects a practicing software engineer to have. The most current SWEBOK v3 is an updated version and was released in 2014.[28] The IEEE also promulgates a "Software Engineering Code of Ethics".[29]

Employment

In 2004, the U. S. Bureau of Labor Statistics counted 760,840 software engineers holding jobs in the U.S.; in the same time period there were some 1.4 million practitioners employed in the U.S. in all other engineering disciplines combined.[30] Due to its relative newness as a field of study, formal education in software engineering is often taught as part of a computer science curriculum, and many software engineers hold computer science degrees and have no engineering background whatsoever.[31]

Many software engineers work as employees or contractors. Software engineers work with businesses, government agencies (civilian or military), and non-profit organizations. Some software engineers work for themselves as freelancers. Some organizations have specialists to perform each of the tasks in the software development process. Other organizations require software engineers to do many or all of them. In large projects, people may specialize in only one role. In small projects, people may fill several or all roles at the same time. Specializations include: in industry (analysts, architects, developers, testers, technical support, middleware analysts, managers) and in academia (educators, researchers).

Most software engineers and programmers work 40 hours a week, but about 15 percent of software engineers and 11 percent of programmers worked more than 50 hours a week in 2008. Injuries in these occupations are rare. However, like other workers who spend long periods in front of a computer terminal typing at a keyboard, engineers and programmers are susceptible to eyestrain, back discomfort, and hand and wrist problems such as carpal tunnel syndrome.[32]

The field's future looks bright according to Money Magazine and Salary.com, which rated Software Engineer as the best job in the United States in 2006.[33] In 2012, software engineering was again ranked as the best job in the United States, this time by CareerCast.com.[34]

Certification

The Software Engineering Institute offers certifications on specific topics like security, process improvement and software architecture.[35] Apple, IBM, Microsoft and other companies also sponsor their own certification examinations. Many IT certification programs are oriented toward specific technologies, and managed by the vendors of these technologies.[36] These certification programs are tailored to the institutions that would employ people who use these technologies.

Broader certification of general software engineering skills is available through various professional societies. As of 2006, the IEEE had certified over 575 software professionals as a Certified Software Development Professional (CSDP).[37] In 2008 they added an entry-level certification known as the Certified Software Development Associate (CSDA).[38] The ACM had a professional certification program in the early 1980s,[citation needed] which was discontinued due to lack of interest. The ACM examined the possibility of professional certification of software engineers in the late 1990s, but eventually decided that such certification was inappropriate for the professional industrial practice of software engineering.[39]

In the U.K. the British Computer Society has developed a legally recognized professional certification called Chartered IT Professional (CITP), available to fully qualified members (MBCS). Software engineers may be eligible for membership of the Institution of Engineering and Technology and so qualify for Chartered Engineer status. In Canada the Canadian Information Processing Society has developed a legally recognized professional certification called Information Systems Professional (ISP).[40] In Ontario, Canada, Software Engineers who graduate from a Canadian Engineering Accreditation Board (CEAB) accredited program, successfully complete PEO's (Professional Engineers Ontario) Professional Practice Examination (PPE) and have at least 48 months of acceptable engineering experience are eligible to be licensed through the Professional Engineers Ontario and can become Professional Engineers P.Eng.[41] The PEO does not recognize any online or distance education however; and does not consider Computer Science programs to be equivalent to software engineering programs despite the tremendous overlap between the two. This has sparked controversy and a certification war. It has also held the number of P.Eng holders for the profession exceptionally low. The vast majority of working professionals in the field hold a degree in CS, not SE. Given the difficult certification path for holders of non-SE degrees, most never bother to pursue the license.

Impact of globalization

The initial impact of outsourcing, and the relatively lower cost of international human resources in developing third world countries led to a massive migration of software development activities from corporations in North America and Europe to India and later: China, Russia, and other developing countries. This approach had some flaws, mainly the distance / timezone difference that prevented human interaction between clients and developers and the massive job transfer. This had a negative impact on many aspects of the software engineering profession. For example, some students in the developed world avoid education related to software engineering because of the fear of offshore outsourcing (importing software products or services from other countries) and of being displaced by foreign visa workers.[42] Although statistics do not currently show a threat to software engineering itself; a related career, computer programming does appear to have been affected.[43][44] Nevertheless, the ability to smartly leverage offshore and near-shore resources via the follow-the-sun workflow has improved the overall operational capability of many organizations.[45] When North Americans are leaving work, Asians are just arriving to work. When Asians are leaving work, Europeans are arriving to work. This provides a continuous ability to have human oversight on business-critical processes 24 hours per day, without paying overtime compensation or disrupting a key human resource, sleep patterns.

While global outsourcing has several advantages, global - and generally distributed - development can run into serious difficulties resulting from the distance between developers. This is due to the key elements of this type of distance which have been identified as geographical, temporal, cultural and communication (which includes the use of different languages and dialects of English in different locations).[46] Research has been carried out in the area of global software development over the last 15 years and an extensive body of relevant work published which highlights the benefits and problems associated with the complex activity. As with other aspects of software engineering research is ongoing in this and related areas.

Related fields

Software engineering is a direct sub-field of engineering and has an overlap with computer science and management science[citation needed]. It is also considered a part of overall systems engineering.

Controversy

Typical formal definitions of software engineering are:

"the application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software".[6]
"an engineering discipline that is concerned with all aspects of software production"[7]
"the establishment and use of sound engineering principles in order to economically obtain software that is reliable and works efficiently on real machines"[8]

The term has been used less formally:

as the informal contemporary term for the broad range of activities that were formerly called computer programming and systems analysis;[47]
as the broad term for all aspects of the practice of computer programming, as opposed to the theory of computer programming, which is called computer science;[48]
as the term embodying the advocacy of a specific approach to computer programming, one that urges that it be treated as an engineering discipline rather than an art or a craft, and advocates the codification of recommended practices.[49]

Criticism

Software Engineering sees its practitioners as individuals who follow well-defined engineering approaches to problem-solving. These approaches are specified in various software engineering books and research papers, always with the connotations of predictability, precision, mitigated risk and professionalism. This perspective has led to calls for licensing, certification and codified bodies of knowledge as mechanisms for spreading the engineering knowledge and maturing the field.

Software Craftsmanship has been proposed by a body of software developers as an alternative that emphasizes the coding skills and accountability of the software developers themselves without professionalism or any prescribed curriculum leading to ad-hoc problem-solving (craftmanship) without engineering (lack of predictability, precision, missing risk mitigation, methods are informal and poorly defined). The Software Craftsmanship Manifesto extends the Agile Software Manifesto[50] and draws a metaphor between modern software development and the apprenticeship model of medieval Europe.

Software engineering extends engineering and draws on the engineering model, i.e. engineering process, engineering project management, engineering requirements, engineering design, engineering construction, and engineering validation. The concept is so new that it is rarely understood, and it is widely misinterpreted, including in software engineering textbooks, papers, and among the communities of programmers and crafters.

One of the core issues in software engineering is that its approaches are not empirical enough because a real-world validation of approaches is usually absent, or very limited and hence software engineering is often misinterpreted as feasible only in a "theoretical environment."

Dijkstra who developed computer languages in the last century refuted the concepts of "software engineering" which was prevalent thirty years ago in the 1980s, arguing that those terms were poor analogies for what he called the "radical novelty" of computer science:

A number of these phenomena have been bundled under the name "Software Engineering". As economics is known as "The Miserable Science", software engineering should be known as "The Doomed Discipline", doomed because it cannot even approach its goal since its goal is self-contradictory. Software engineering, of course, presents itself as another worthy cause, but that is eyewash: if you carefully read its literature and analyse what its devotees actually do, you will discover that software engineering has accepted as its charter "How to program if you cannot."[51]

See also

Portal icon Software portal
Portal icon Software Testing portal
Main article: Outline of software engineering
Bachelor of Science in Information Technology
Bachelor of Software Engineering
List of software engineering conferences
List of software engineering publications
Software craftsmanship
Software Engineering Institute

Notes

a b Abran et al. 2004, pp. 1–1
ACM (2007). "Computing Degrees & Careers". ACM. Retrieved 2010-11-23.
Laplante, Phillip (2007). What Every Engineer Should Know about Software Engineering. Boca Raton: CRC. ISBN 978-0-8493-7228-5. Retrieved 2011-01-21.
The Bureau of Labor Statistics
“Systems and software engineering - Vocabulary,” ISO/IEC/IEEE std 24765:2010(E), 2010.
 a b “IEEE Standard Glossary of Software Engineering Terminology,” IEEE std 610.12-1990, 1990.
 a b Sommerville, Ian (2007) [1982]. "1.1.2 What is software engineering?". Software Engineering (8th ed.). Harlow, England: Pearson Education. p. 7. ISBN 0-321-31379-8. Software engineering is an engineering discipline that is concerned with all aspects of software production from the early stages of system specification to maintaining the system after it has gone into use. In this definition, there are two key phrases:
1. Engineering discipline Engineers make things work. They apply theories, methods and tools where these are appropriate [. . .] Engineers also recognize that they must work to organizational and financial constraints. [. . .]
2. All aspects of software production Software engineering is not just concerned with the technical processes of software development but also with activities such as software project management and with the development of tools, methods and theories to support software production. line feed character in |quote= at position 259 (help)
 a b "Software Engineering". Information Processing (North-Holland Publishing Co.) 71: 530–538. 1972.
 a b Oettinger, Anthony (1967). "The hardware-software complementarity". Communications of the ACM 10 (10): 604–606. doi:10.1145/363717.363722.
 Leondes (2002). intelligent systems: technology and applications. CRC Press. p. I-6. ISBN 978-0-8493-1121-5. 1.4 Computers and a First Glimpse at Al (1940s)
 Dijkstra, E. W. (March 1968). "Go To Statement Considered Harmful" (PDF). Communications of the ACM 11 (3): 147–148. doi:10.1145/362929.362947. Retrieved 2009-08-10.
 Parnas, David (December 1972). "On the Criteria To Be Used in Decomposing Systems into Modules". Communications of the ACM 15 (12): 1053–1058. doi:10.1145/361598.361623. Retrieved 2008-12-26.
 Rayl, A.J.S. (October 16, 2008). "NASA Engineers and Scientists-Transforming Dreams Into Reality". NASA. NASA. Retrieved December 27, 2014.
 "Margaret Hamilton, the Engineer Who Took the Apollo to the Moon". Retrieved January 15, 2015.
 "Software Engineering" (PDF).
 Tedre, Matti (2014). Science of Computing: Shaping a Discipline. CRC Press. ISBN 978-1482217698.
 Sommerville 2008, p. 26
 Peter, Naur; Brian Randell (7–11 October 1968). Software Engineering: Report of a conference sponsored by the NATO Science Committee (PDF). Garmisch, Germany: Scientific Affairs Division, NATO. Retrieved 2008-12-26.
 Randell, Brian (10 August 2001). "The 1968/69 NATO Software Engineering Reports". Brian Randell's University Homepage. The School of the Computer Sciences, Newcastle University. Retrieved 2008-10-11. The idea for the first NATO Software Engineering Conference, and in particular that of adopting the then practically unknown term "software engineering" as its (deliberately provocative) title, I believe came originally from Professor Fritz Bauer.
 Boehm (1981). Software Engineering Economics. Prentice-Hall. ISBN 0-13-822122-7.
 Humphrey, Watts S. (1989). Managing the Software Process. Addison-Wesley. ISBN 0-201-18095-2.
 "ISO/IEC TR 19759:2005". Retrieved 2012-04-01.
 Abran, Alain, ed. (2005) [2004]. "Chapter 1: Introduction to the Guide". Guide to the Software Engineering Body of Knowledge. Los Alamitos: IEEE Computer Society. ISBN 0-7695-2330-7. Retrieved 2010-09-13. The total volume of cited literature is intended to be suitable for mastery through the completion of an undergraduate education plus four years of experience.
 "SE2004 Software Engineering Curriculum". Sites.computer.org. 2003-09-30. Retrieved 2012-03-25.
 [1] Degree programs in Software Engineering
 Williams, N.S.W. (19–21 February 2001). "Professional Engineers Ontario's approach to licensing software engineering practitioners". Software Engineering Education and Training, 2001 Proceedings. 14th Conference on. Charlotte, NC: IEEE. pp. 77–78.
 "NCEES Software Engineering Exam Specifications" (PDF). Retrieved 2012-04-01.
 "'SWEBOK Guide Version 3'". Retrieved 2015-03-09.
 "''Software Engineering Code of Ethics''" (PDF). Retrieved 2012-03-25.
 Bureau of Labor Statistics, U.S. Department of Labor, USDL 05-2145: Occupational Employment and Wages, November 2004, Table 1.
 "Software Engineering". Retrieved 2008-02-01.
 "Computer Software Engineers and Computer Programmers". Retrieved 2009-12-17.
 Kalwarski, Tara; Daphne Mosher; Janet Paskin; Donna Rosato (2006). "Best Jobs in America". MONEY Magazine. CNN. Retrieved 2006-04-20.
 "Best and Worst Jobs of 2012". online.wsj.com. Retrieved 2012.
 "SEI certification page". Sei.cmu.edu. Retrieved 2012-03-25.
 Wyrostek, Warren (March 14, 2008). "The Top 10 Problems with IT Certification in 2008". InformIT. Retrieved 2009-03-03.
 IEEE Computer Society. "2006 IEEE computer society report to the IFIP General Assembly" (PDF). Retrieved 2007-04-10.
 IEEE. "CSDA". Retrieved 2010-04-20.
 ACM (July 17, 2000). "A Summary of the ACM Position on Software Engineering as a Licensed Engineering Profession" (PDF). Association for Computing Machinery (ACM). Archived from the original (PDF) on May 17, 2008. Retrieved 2009-03-03. At its meeting in May 2000, the Council further concluded that the framework of a licensed professional engineer, originally developed for civil engineers, does not match the professional industrial practice of software engineering. Such licensing practices would give false assurances of competence even if the body of knowledge were mature; and would preclude many of the most qualified software engineers from becoming licensed.
 Canadian Information Processing Society. "I.S.P. Designation". Retrieved 2007-03-15.
 "Professional Engineers Ontario: Welcome to PEO's website". Peo.on.ca. Retrieved 2012-03-25.
 Thibodaux, Patrick (2006-05-05). "As outsourcing gathers steam, computer science interest wanes". Computerworld.com. Retrieved 2012-03-25.
 "Computer Programmers". Bls.gov. Retrieved 2012-03-25.
 Mullins, Robert (2007-03-13). "Software developer growth slows in North America". InfoWorld. Retrieved 2012-03-25.
 "Gartner Magic Quadrant" (PDF). Cognizant.com. Retrieved 2012-03-25.
 Casey, Valentine (2010-08-20). "Virtual software team project management". Springer. Retrieved 2013-12-06.
 Akram I. Salah (2002-04-05). "Engineering an Academic Program in Software Engineering" (PDF). 35th Annual Midwest Instruction and Computing Symposium. Retrieved 2006-09-13.: "For some, software engineering is just a glorified name for programming. If you are a programmer, you might put 'software engineer' on your business card—never 'programmer' though."
 Mills, Harlan D., J. R. Newman, and C. B. Engle, Jr., "An Undergraduate Curriculum in Software Engineering," in Deimel, Lionel E. (1990). Software Engineering Education: SEI Conference 1990, Pittsburgh, Pennsylvania, USA, April 2–3,... Springer. ISBN 0-387-97274-9.,p. 26: "As a practical matter, we regard software engineering as the necessary preparation for the practicing, software development and maintenance professional. The Computer Scientist is preparing for further theoretical studies..."
 David Budgen, Pearl Brereton, Barbara Kitchenham, Stephen Linkman (2004-12-14). "Realizing Evidence-based Software Engineering". Retrieved 2006-10-18. : "We believe that software engineering can only advance as an engineering discipline by moving away from its current dependence upon advocacy and analysis,...."
 Beck, Kent; et al. (2001). "Manifesto for Agile Software Development". Agile Alliance. Retrieved 14 June 2010.
 Dijkstra, E. W. (1988). "On the cruelty of really teaching computing science". Retrieved 2014-01-10.
References[edit]
Abran, Alain; Moore, James W.; Bourque, Pierre; Dupuis, Robert; Tripp, Leonard L. (2004). Guide to the Software Engineering Body of Knowledge. IEEE. ISBN 0-7695-2330-7.
Sommerville, Ian (2008). Software Engineering (7 ed.). Pearson Education. ISBN 978-81-7758-530-8. Retrieved 10 January 2013.
Further reading[edit]
Ghezzi, Carlo; Mehdi Jazayeri; Dino Mandrioli (2003) [1991]. Fundamentals of Software Engineering (2nd (International) ed.). Pearson Education @ Prentice-Hall.
Jalote, Pankaj (2005) [1991]. An Integrated Approach to Software Engineering (3rd ed.). Springer. ISBN 0-387-20881-X.
Pressman, Roger S (2009). Software Engineering: A Practitioner's Approach (7th ed.). Boston, Mass: McGraw-Hill. ISBN 978-0073375977.
Sommerville, Ian (2010) [2010]. Software Engineering (9th ed.). Harlow, England: Pearson Education. ISBN 978-0137035151.
Bruegge, Bernd; Dutoit, Allen (2009). Object-oriented software engineering : using UML, patterns, and Java (3rd ed.). Prentice Hall. ISBN 978-0136061250.

From Wikipedia, the free encyclopedia
.

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What is Software Development?

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Software development

Software development is the process of computer programming, documenting, testing, and bug fixing involved in creating and maintaining applications and frameworks involved in a software release life cycle and resulting in a software product. The term refers to a process of writing and maintaining the source code, but in a broader sense of the term it includes all that is involved between the conception of the desired software through to the final manifestation of the software, ideally in a planned and structured process.[1] Therefore, software development may include research, new development, prototyping, modification, reuse, re-engineering, maintenance, or any other activities that result in software products.[2]

Software can be developed for a variety of purposes, the three most common being to meet specific needs of a specific client/business (the case with custom software), to meet a perceived need of some set of potential users (the case with commercial and open source software), or for personal use (e.g. a scientist may write software to automate a mundane task). Embedded software development, that is, the development of embedded software such as used for controlling consumer products, requires the development process to be integrated with the development of the controlled physical product. System software underlies applications and the programming process itself, and is often developed separately.

The need for better quality control of the software development process has given rise to the discipline of software engineering, which aims to apply the systematic approach exemplified in the engineering paradigm to the process of software development.

There are many approaches to software project management, known as software development life cycle models, methodologies, processes, or models. The waterfall model is a traditional version, contrasted with the more recent innovation of agile software development.

Contents

1 Methodologies
2 Software development activities
2.1 Identification of need
2.2 Planning
2.3 Designing
2.4 Implementation, testing and documenting
2.5 Deployment and maintenance
2.6 Other
3 Subtopics
3.1 View model
3.2 Business process and data modelling
3.3 Computer-aided software engineering
3.4 Integrated development environment
3.5 Modeling language
3.6 Programming paradigm
3.7 Software framework
4 See also
4.1 Roles and industry
4.2 Specific applications
5 References
6 Further reading

Methodologies

A software development process (also known as a software development methodology, model, or life cycle) is a framework that is used to structure, plan, and control the process of developing information systems. A wide variety of such frameworks have evolved over the years, each with its own recognized strengths and weaknesses. There are several different approaches to software development: some take a more structured, engineering-based approach to developing business solutions, whereas others may take a more incremental approach, where software evolves as it is developed piece-by-piece. One system development methodology is not necessarily suitable for use by all projects. Each of the available methodologies is best suited to specific kinds of projects, based on various technical, organizational, project and team considerations.

Most methodologies share some combination of the following stages of software development:

Analyzing the problem
Market research
Gathering requirements for the proposed business solution
Devising a plan or design for the software-based solution
Implementation (coding) of the software
Testing the software
Deployment
Maintenance and bug fixing


These stages are often referred to collectively as the software development lifecycle, or SDLC. Different approaches to software development may carry out these stages in different orders, or devote more or less time to different stages. The level of detail of the documentation produced at each stage of software development may also vary. These stages may also be carried out in turn (a “waterfall” based approach), or they may be repeated over various cycles or iterations (a more "extreme" approach). The more extreme approach usually involves less time spent on planning and documentation, and more time spent on coding and development of automated tests. More “extreme” approaches also promote continuous testing throughout the development lifecycle, as well as having a working (or bug-free) product at all times. More structured or “waterfall” based approaches attempt to assess the majority of risks and develop a detailed plan for the software before implementation (coding) begins, and avoid significant design changes and re-coding in later stages of the software development life cycle planning.

There are significant advantages and disadvantages to the various methodologies, and the best approach to solving a problem using software will often depend on the type of problem. If the problem is well understood and a solution can be effectively planned out ahead of time, the more "waterfall" based approach may work the best. If, on the other hand, the problem is unique (at least to the development team) and the structure of the software solution cannot be easily envisioned, then a more "extreme" incremental approach may work best.

Software development activities

Identification of need

The sources of ideas for software products are legion.[3] 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, for fit with existing channels distribution, for possible effects on existing product lines, required features, and for fit with the company's marketing objectives. In a marketing evaluation phase, the cost and time assumptions become evaluated. A decision is reached early in the first phase as to whether, based on the more detailed information generated by the marketing and development staff, the project should be pursued further.[3]

In the book "Great Software Debates", Alan M. Davis states in the chapter "Requirements", subchapter "The Missing Piece of Software Development"

Students of engineering learn engineering and are rarely exposed to finance or marketing. Students of marketing learn marketing and are rarely exposed to finance or engineering. Most of us become specialists in just one area. To complicate matters, few of us meet interdisciplinary people in the workforce, so there are few roles to mimic. Yet, software product planning is critical to the development success and absolutely requires knowledge of multiple disciplines.[4]

Because software development may involve compromising or going beyond what is required by the client, a software development project may stray into less technical concerns such as human resources, risk management, intellectual property, budgeting, crisis management, etc. These processes may also cause the role of business development to overlap with software development.

Planning

Planning is an objective of each and every activity, where we want to discover things that belong to the project. An important task in creating a software program is extracting the requirements or requirements analysis.[5] Customers typically have an abstract idea of what they want as an end result, but do not know what software should do. Skilled and experienced software engineers recognize incomplete, ambiguous, or even contradictory requirements at this point. Frequently demonstrating live code may help reduce the risk that the requirements are incorrect.

Once the general requirements are gathered from the client, an analysis of the scope of the development should be determined and clearly stated. This is often called a scope document.

Certain functionality may be out of scope of the project as a function of cost or as a result of unclear requirements at the start of development. If the development is done externally, this document can be considered a legal document so that if there are ever disputes, any ambiguity of what was promised to the client can be clarified.

Designing

Once the requirements are established, the design of the software can be established in a software design document. This involves a preliminary, or high-level design of the main modules with an overall picture (such as a block diagram) of how the parts fit together. The language, operating system, and hardware components should all be known at this time. Then a detailed or low-level design is created, perhaps with prototyping as proof-of-concept or to firm up requirements.

Implementation, testing and documenting

Implementation is the part of the process where software engineers actually program the code for the project.

Software testing is an integral and important phase of the software development process. This part of the process ensures that defects are recognized as soon as possible. In some processes, generally known as test-driven development, tests may be developed just before implementation and serve as a guide for the implementation's correctness.

Documenting the internal design of software for the purpose of future maintenance and enhancement is done throughout development. This may also include the writing of an API, be it external or internal. The software engineering process chosen by the developing team will determine how much internal documentation (if any) is necessary. Plan-driven models (e.g., Waterfall) generally produce more documentation than Agile models.

Deployment and maintenance

Deployment starts directly after the code is appropriately tested, approved for release, and sold or otherwise distributed into a production environment. This may involve installation, customization (such as by setting parameters to the customer's values), testing, and possibly an extended period of evaluation.

Software training and support is important, as software is only effective if it is used correctly.

Maintaining and enhancing software to cope with newly discovered faults or requirements can take substantial time and effort, as missed requirements may force redesign of the software.



Software Development is estimated to be a vastly expanding area. With how rapidly technology is changing, this skill has become more and more needed.

Subtopics

View model

The TEAF Matrix of Views and Perspectives.
A view model is a framework that provides the viewpoints on the system and its environment, to be used in the software development process. It is a graphical representation of the underlying semantics of a view.

The purpose of viewpoints and views is to enable human engineers to comprehend very complex systems, and to organize the elements of the problem and the solution around domains of expertise. In the engineering of physically intensive systems, viewpoints often correspond to capabilities and responsibilities within the engineering organization.[6]

Most complex system specifications are so extensive that no one individual can fully comprehend all aspects of the specifications. Furthermore, we all have different interests in a given system and different reasons for examining the system's specifications. A business executive will ask different questions of a system make-up than would a system implementer. The concept of viewpoints framework, therefore, is to provide separate viewpoints into the specification of a given complex system. These viewpoints each satisfy an audience with interest in some set of aspects of the system. Associated with each viewpoint is a viewpoint language that optimizes the vocabulary and presentation for the audience of that viewpoint.

Business process and data modelling

Graphical representation of the current state of information provides a very effective means for presenting information to both users and system developers.


example of the interaction between business process and data models.[7]
A business model illustrates the functions associated with the business process being modeled and the organizations that perform these functions. By depicting activities and information flows, a foundation is created to visualize, define, understand, and validate the nature of a process.

A data model provides the details of information to be stored, and is of primary use when the final product is the generation of computer software code for an application or the preparation of a functional specification to aid a computer software make-or-buy decision. See the figure on the right for an example of the interaction between business process and data models.[7]

Usually, a model is created after conducting an interview, referred to as business analysis. The interview consists of a facilitator asking a series of questions designed to extract required information that describes a process. The interviewer is called a facilitator to emphasize that it is the participants who provide the information. The facilitator should have some knowledge of the process of interest, but this is not as important as having a structured methodology by which the questions are asked of the process expert. The methodology is important because usually a team of facilitators is collecting information across the facility and the results of the information from all the interviewers must fit together once completed.[7]

The models are developed as defining either the current state of the process, in which case the final product is called the "as-is" snapshot model, or a collection of ideas of what the process should contain, resulting in a "what-can-be" model. Generation of process and data models can be used to determine if the existing processes and information systems are sound and only need minor modifications or enhancements, or if re-engineering is required as a corrective action. The creation of business models is more than a way to view or automate your information process. Analysis can be used to fundamentally reshape the way your business or organization conducts its operations.[7]

Computer-aided software engineering

Computer-aided software engineering (CASE), in the field software engineering is the scientific application of a set of software tools and methods to the development of software which results in high-quality, defect-free, and maintainable software products.[8] It also refers to methods for the development of information systems together with automated tools that can be used in the software development process.[9] The term "computer-aided software engineering" (CASE) can refer to the software used for the automated development of systems software, i.e., computer code. The CASE functions include analysis, design, and programming. CASE tools automate methods for designing, documenting, and producing structured computer code in the desired programming language.[10]

Two key ideas of Computer-aided Software System Engineering (CASE) are:[11]

Foster computer assistance in software development and or software maintenance processes, and An engineering approach to software development and or maintenance.

Typical CASE tools exist for configuration management, data modeling, model transformation, refactoring, source code generation.

Integrated development environment

An integrated development environment (IDE) also known as integrated design environment or integrated debugging environment is a software application that provides comprehensive facilities to computer programmers for software development. An IDE normally consists of a:

source code editor,
compiler and/or interpreter,
build automation tools, and
debugger (usually).

IDEs are designed to maximize programmer productivity by providing tight-knit components with similar user interfaces. Typically an IDE is dedicated to a specific programming language, so as to provide a feature set which most closely matches the programming paradigms of the language.

Modeling language

A modeling language is any artificial language that can be used to express information or knowledge or systems in a structure that is defined by a consistent set of rules. The rules are used for interpretation of the meaning of components in the structure. A modeling language can be graphical or textual.[12] Graphical modeling languages use a diagram techniques with named symbols that represent concepts and lines that connect the symbols and that represent relationships and various other graphical annotation to represent constraints. Textual modeling languages typically use standardised keywords accompanied by parameters to make computer-interpretable expressions.

Example of graphical modelling languages in the field of software engineering are:

Business Process Modeling Notation (BPMN, and the XML form BPML) is an example of a process modeling language.
EXPRESS and EXPRESS-G (ISO 10303-11) is an international standard general-purpose data modeling language.
Extended Enterprise Modeling Language (EEML) is commonly used for business process modeling across layers.

Flowchart is a schematic representation of an algorithm or a stepwise process,
Fundamental Modeling Concepts (FMC) modeling language for software-intensive systems.
IDEF is a family of modeling languages, the most notable of which include IDEF0 for functional modeling, IDEF1X for information modeling, and IDEF5 for modeling ontologies.
LePUS3 is an object-oriented visual Design Description Language and a formal specification language that is suitable primarily for modelling large object-oriented (Java, C++, C#) programs and design patterns.

Specification and Description Language(SDL) is a specification language targeted at the unambiguous specification and description of the behaviour of reactive and distributed systems.

Unified Modeling Language (UML) is a general-purpose modeling language that is an industry standard for specifying software-intensive systems. UML 2.0, the current version, supports thirteen different diagram techniques, and has widespread tool support.

Not all modeling languages are executable, and for those that are, using them doesn't necessarily mean that programmers are no longer needed. On the contrary, executable modeling languages are intended to amplify the productivity of skilled programmers, so that they can address more difficult problems, such as parallel computing and distributed systems.

Programming paradigm

A programming paradigm is a fundamental style of computer programming, which is not generally dictated by the project management methodology (such as waterfall or agile). Paradigms differ in the concepts and abstractions used to represent the elements of a program (such as objects, functions, variables, constraints) and the steps that comprise a computation (such as assignations, evaluation, continuations, data flows). Sometimes the concepts asserted by the paradigm are utilized cooperatively in high-level system architecture design; in other cases, the programming paradigm's scope is limited to the internal structure of a particular program or module.

A programming language can support multiple paradigms. For example, programs written in C++ or Object Pascal can be purely procedural, or purely object-oriented, or contain elements of both paradigms. Software designers and programmers decide how to use those paradigm elements. In object-oriented programming, programmers can think of a program as a collection of interacting objects, while in functional programming a program can be thought of as a sequence of stateless function evaluations. When programming computers or systems with many processors, process-oriented programming allows programmers to think about applications as sets of concurrent processes acting upon logically shared data structures.

Just as different groups in software engineering advocate different methodologies, different programming languages advocate different programming paradigms. Some languages are designed to support one paradigm (Smalltalk supports object-oriented programming, Haskell supports functional programming), while other programming languages support multiple paradigms (such as Object Pascal, C++, C#, Visual Basic, Common Lisp, Scheme, Python, Ruby, and Oz).

Many programming paradigms are as well known for what methods they forbid as for what they enable. For instance, pure functional programming forbids using side-effects; structured programming forbids using goto statements. Partly for this reason, new paradigms are often regarded as doctrinaire or overly rigid by those accustomed to earlier styles.[citation needed] Avoiding certain methods can make it easier to prove theorems about a program's correctness, or simply to understand its behavior.

Examples of high-level paradigms include:

Aspect-oriented software development
Domain-specific modeling
Model-driven engineering
Object-oriented programming methodologies
Grady Booch's object-oriented design (OOD), also known as object-oriented analysis and design (OOAD). The Booch model includes six diagrams: class, object, state transition, interaction, module, and process.[13]
Search-based software engineering
Service-oriented modeling
Structured programming
Top-down and bottom-up design
Top-down programming: evolved in the 1970s by IBM researcher Harlan Mills (and Niklaus Wirth) in developed structured programming.

Software framework

A software framework is a re-usable design or implementation for a software system or subsystem. A software framework may include support programs, code libraries, a scripting language, or other software to help develop and glue together the different components of a software project. Frameworks can reduce, consolidate, and standardize logic as well as execute proprietary implementations without exposing their intellectual property or sensitive implantation variables. Various parts and components of the framework may be exposed via an API. These exposed interfaces are considered 'public' and represent a common protocol of information and procedure; they are typically 'exposed' through declarations, protocols, and public methods. Similar to an iceberg, a great deal of a framework's actual implementation and/or logic may not be 'visible' through an API. This portion of a framework is considered 'Private', even though the framework may be open-source or physically visible to the developer/implementer, the 'public vs. private' identification distinctions are based on what is exposed to the consuming resource.

See also:

Best coding practices
Continuous integration
Custom software
Functional specification
Programming productivity
Software blueprint
Software design
Software development effort estimation
Software development process
Software project management
Specification and Description Language
User experience

Roles and industry:

Bachelor of Science in Information Technology
Computer programmer
Consulting software engineer
Offshore software development
Software developer
Software engineer
Software industry
Software publisher

Specific applications:

Video game development
Web application development
Web engineering

References

"Application Development (AppDev) Defined and Explained". Bestpricecomputers.co.uk. 2007-08-13. Retrieved 2012-08-05.
DRM Associates (2002). "New Product Development Glossary". Retrieved 2006-10-29.
a b Joseph M. Morris (2001). Software Industry Accounting. p.1.10
Alan M. Davis. Great Software Debates (October 8, 2004), pp:125-128 Wiley-IEEE Computer Society Press
Ralph, P., and Wand, Y. A Proposal for a Formal Definition of the Design Concept. In, Lyytinen, K., Loucopoulos, P., Mylopoulos, J., and Robinson, W., (eds.), Design Requirements Engineering: A Ten-Year Perspective: Springer-Verlag, 2009, pp. 103-136
Edward J. Barkmeyer ea (2003). Concepts for Automating Systems Integration NIST 2003.
a b c d Paul R. Smith & Richard Sarfaty (1993). Creating a strategic plan for configuration management using Computer Aided Software Engineering (CASE) tools. Paper For 1993 National DOE/Contractors and Facilities CAD/CAE User's Group.
Kuhn, D.L (1989). "Selecting and effectively using a computer aided software engineering tool". Annual Westinghouse computer symposium; 6-7 Nov 1989; Pittsburgh, PA (USA); DOE Project.
P. Loucopoulos and V. Karakostas (1995). System Requirements Engineering. McGraw-Hill.
CASE definition In: Telecom Glossary 2000. Retrieved 26 Oct 2008.
K. Robinson (1992). Putting the Software Engineering into CASE. New York : John Wiley and Sons Inc.
Xiao He (2007). "A metamodel for the notation of graphical modeling languages". In: Computer Software and Applications Conference, 2007. COMPSAC 2007 – Vol. 1. 31st Annual International, Volume 1, Issue , 24–27 July 2007, pp 219-224.
Georges Gauthier Merx & Ronald J. Norman (2006). Unified Software Engineering with Java. p.201.

Further reading

Edward Kit (1992). Software Testing in The Real World.
Jim McCarthy (1995). Dynamics of Software Development.
Dan Conde (2002). Software Product Management: Managing Software Development from Idea to Product to Marketing to Sales.
A.M. Davis (2005). Just enough requirements management: where software development meets marketing.
Edward Hasted. (2005). Software That Sells : A Practical Guide to Developing and Marketing Your Software Project.
Luke Hohmann (2003). Beyond Software Architecture: Creating and Sustaining Winning Solutions.
John W. Horch (2005). "Two Orientations On How To Work With Objects." In: IEEE Software. vol. 12, no. 2, pp. 117–118, Mar., 1995.
John Rittinghouse (2003). Managing Software Deliverables: A Software Development Management Methodology.
Karl E. Wiegers (2005). More About Software Requirements: Thorny Issues and Practical Advice.
Robert K. Wysocki (2006). Effective Software Project Management.
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From Wikipedia, the free encyclopedia
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Application software

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Application software

An application program (app or application for short) is a computer program designed to perform a group of coordinated functions, tasks, or activities for the benefit of the user. Examples of an application include a word processor, a spreadsheet, an accounting application, a web browser, a media player, an aeronautical flight simulator, a console game or a photo editor. The collective noun application software refers to all applications collectively.[1] This contrasts with system software, which is mainly involved with running the computer.

Applications may be bundled with the computer and its system software or published separately, and may be coded as proprietary, open-source or university projects.[2]

Contents

1 Terminology
1.1 Metonymy
1.2 Apps and killer apps
2 Classification
2.1 Information worker software
2.2 Entertainment software
2.3 Educational software
2.4 Enterprise infrastructure software
2.5 Simulation software
2.6 Media development software
2.7 Product engineering software
3 See also
4 References
5 External link

Terminology

In information technology, an application is a computer program designed to help people perform an activity. An application thus differs from an operating system (which runs a computer), a utility (which performs maintenance or general-purpose chores), and a programming tool (with which computer programs are created)[original research?]. Depending on the activity for which it was designed, an application can manipulate text, numbers, graphics, or a combination of these elements. Some application packages focus on a single task, such as word processing; others, called integrated software include several applications.[3]

User-written software tailors systems to meet the user's specific needs. User-written software includes spreadsheet templates, word processor macros, scientific simulations, graphics and animation scripts. Even email filters are a kind of user software. Users create this software themselves and often overlook how important it is.

The delineation between system software such as operating systems and application software is not exact, however, and is occasionally the object of controversy.[4] For example, one of the key questions in the United States v. Microsoft antitrust trial was whether Microsoft's Internet Explorer web browser was part of its Windows operating system or a separable piece of application software. As another example, the GNU/Linux naming controversy is, in part, due to disagreement about the relationship between the Linux kernel and the operating systems built over this kernel. In some types of embedded systems, the application software and the operating system software may be indistinguishable to the user, as in the case of software used to control a VCR, DVD player or microwave oven. The above definitions may exclude some applications that may exist on some computers in large organizations. For an alternative definition of an app: see Application Portfolio Management.

Metonymy

The word "application", once used as an adjective, is not restricted to the "of or pertaining to application software" meaning.[5] For example, concepts such as application programming interface (API), application server, application virtualization, application lifecycle management and portable application apply to all computer programs alike, not just application software.

Apps and killer apps

Some applications are available in versions for several different platforms; others have narrower requirements and are thus called, for example, a Geography application for Windows, an Android application for education, or Linux gaming. Sometimes a new and popular application arises which only runs on one platform, increasing the desirability of that platform. This is called a killer application or killer app.

In recent years, the shortened term "app" (coined in 1981 or earlier[6]) has become popular to refer to applications for mobile devices such as smartphones and tablets, the shortened form matching their typically smaller scope compared to applications on PCs.

Classification

There are many different ways to divide up different types of application software, and several are explained here.

Since the development and near-universal adoption of the web, an important distinction that has emerged has been between web applications — written with HTML, JavaScript and other web-native technologies and typically requiring one to be online and running a web browser, and the more traditional native applications written in whatever languages are available for one's particular type of computer. There has been contentious debate in the computing community regarding web applications replacing native applications for many purposes, especially on mobile devices such as smart phones and tablets. Web apps have indeed greatly increased in popularity for some uses, but the advantages of applications make them unlikely to disappear soon, if ever. Furthermore, the two can be complementary, and even integrated.[7][8][9]

Application software can also be seen as being either horizontal or vertical.[10][11] Horizontal applications are more popular and widespread, because they are general purpose, for example word processors or databases. Vertical applications are niche products, designed for a particular type of industry or business, or department within an organization. Integrated suites of software will try to handle every specific aspect possible of, for example, manufacturing or banking systems, or accounting, or customer service.

There are many types of application software:

An application suite consists of multiple applications bundled together. They usually have related functions, features and user interfaces, and may be able to interact with each other, e.g. open each other's files. Business applications often come in suites, e.g. Microsoft Office, LibreOffice and iWork, which bundle together a word processor, a spreadsheet, etc.; but suites exist for other purposes, e.g. graphics or music.
Enterprise software addresses the needs of an entire organization's processes and data flows, across several departments, often in a large distributed environment. Examples include enterprise resource planning systems, customer relationship management (CRM) systems and supply chain management software. Departmental Software is a sub-type of enterprise software with a focus on smaller organizations and/or groups within a large organization. (Examples include travel expense management and IT Helpdesk.)
Enterprise infrastructure software provides common capabilities needed to support enterprise software systems. (Examples include databases, email servers, and systems for managing networks and security.)

Information worker software lets users create and manage information, often for individual projects within a department, in contrast to enterprise management. Examples include time management, resource management, analytical, collaborative and documentation tools. Word processors, spreadsheets, email and blog clients, personal information system, and individual media editors may aid in multiple information worker tasks.

Content access software is used primarily to access content without editing, but may include software that allows for content editing. Such software addresses the needs of individuals and groups to consume digital entertainment and published digital content. (Examples include media players, web browsers, and help browsers.)

Educational software is related to content access software, but has the content and/or features adapted for use in by educators or students. For example, it may deliver evaluations (tests), track progress through material, or include collaborative capabilities.
Simulation software simulates physical or abstract systems for either research, training or entertainment purposes.

Media development software generates print and electronic media for others to consume, most often in a commercial or educational setting. This includes graphic-art software, desktop publishing software, multimedia development software, HTML editors, digital-animation editors, digital audio and video composition, and many others.[12]

Product engineering software is used in developing hardware and software products. This includes computer-aided design (CAD), computer-aided engineering (CAE), computer language editing and compiling tools, integrated development environments, and application programmer interfaces.

Entertainment Software can refer to video games, screen savers, programs to display motion pictures or play recorded music, and other forms of entertainment which can be experienced through use of a computing device.

Applications can also be classified by computing platform such as a particular operating system, delivery network such as in cloud computing and Web 2.0 applications, or delivery devices such as mobile apps for mobile devices.

The operating system itself can be considered application software when performing simple calculating, measuring, rendering, and word processing tasks not used to control hardware via command-line interface or graphical user interface. This does not include application software bundled within operating systems such as a software calculator or text editor.

Information worker software:

Accounting software
Data management
Contact manager
Spreadsheet
Database software
Documentation
Document automation
Word processor
Desktop publishing software
Diagramming software
Presentation software
Email
Blog software
Enterprise resource planning
Financial software
Day trading software
Banking software
Clearing systems
arithmetic software
Field service management
Workforce management software
Project management software
Calendaring software
Employee scheduling software
Workflow software
Reservation systems

Entertainment software:

Screen savers
Video games
Arcade games
Console games
Mobile games
Personal computer games

Educational software:

Classroom management
Reference software
Sales readiness software
Survey management

Enterprise infrastructure software:

Business workflow software
Database management system (DBMS)
Digital asset management (DAM) software
Document management software
Geographic information system (GIS)
Simulation software[edit]
Computer simulators
Scientific simulators
Social simulators
Battlefield simulators
Emergency simulators
Vehicle simulators
Flight simulators
Driving simulators
Simulation games
Vehicle simulation games

Media development software:

3D computer graphics software
Animation software
Graphic art software
Raster graphics editor
Vector graphics editor
Image organizer
Video editing software
Audio editing software
Digital audio workstation
Music sequencer
Scorewriter
HTML editor
Game development tool

Product engineering software:

Hardware engineering
Computer-aided engineering
Computer-aided design (CAD)
Finite element analysis
Software engineering
Compiler software
Integrated development environment
Compiler
Linker
Version control
Game development tool
Debugger
License manager
See also:
Utility software

References:

"Application software". PC Magazine. Ziff Davis.
Ryan, Thorne (2013-03-14). "Caffeine and computer screens: student programmers endure weekend long appathon". The Arbiter. Retrieved 2015-10-12.
Ceruzzi, Paul E. (2000). A History of Modern Computing. Cambridge, Mass.: MIT Press. ISBN 0-262-03255-4.
Ulrich, William. "Application Package Software: The Promise Vs. Reality". Cutter Consortium.
Application Package Software: The Promise Vs. Reality
The History of 'App' and the Demise of the Programmer
Gassée, Jean-Louis (2012-09-17). "The Silly Web vs. Native Apps Debate". The Silly Web vs. Native Apps Debate. Retrieved 2013-07-14.
Frechette, Casey (2013-04-11). "What journalists need to know about the difference between Web apps and native apps". Poynter. Retrieved 2013-07-14.
Valums, Andrew (2010-02-10). "Web apps vs desktop apps". valums.com. Retrieved 2013-07-14.
"What Is a Horizontal Application?".
"What Are Horizontal Services?".
Campbell-Kelly, Martin; Aspray, William (1996). Computer: A History of the Information Machine. New York: Basic Books. ISBN 0-465-02990-6.

External link:
 Media related to Application software at Wikimedia Commons
 Learning materials related to application software at Wikiversity

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From Wikipedia, the free encyclopedia
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When was the first computer invented?

There is no easy answer to this question due to the many different classifications ofcomputers. The first mechanical computer, created by Charles Babbage in 1822, doesn't really resemble what most would consider a computer today. Therefore, this document has been created with a listing of each of the computer firsts, starting with the Difference Engine and leading up to the computers we use today.

Note: Early inventions which helped lead up to the computer, such as the abacus,calculator, and tablet machines, are not accounted for in this document.

The word "computer" was first used

The word "computer" was first recorded as being used in 1613 and originally was used to describe a human who performed calculations or computations. The definition of a computer remained the same until the end of the 19th century, when the industrial revolution gave rise to machines whose primary purpose was calculating.

First mechanical computer or automatic computing engine concept

In 1822, Charles Babbage conceptualized and began developing the Difference Engine, considered to be the first automatic computing machine. The Difference Engine was capable of computing several sets of numbers and making hard copies of the results. Babbage received some help with development of the Difference Engine from Ada Lovelace, considered by many to be the first computer programmer for her work and notes on the Difference Engine. Unfortunately, because of funding, Babbage was never able to complete a full-scale functional version of this machine. In June of 1991, the London Science Museum completed the Difference Engine No 2 for the bicentennial year of Babbage's birth and later completed the printing mechanism in 2000.

In 1837, Charles Babbage proposed the first general mechanical computer, the Analytical Engine. The Analytical Engine contained an Arithmetic Logic Unit (ALU), basic flow control, and integrated memory and is the first general-purpose computer concept. Unfortunately, because of funding issues, this computer was also never built while Charles Babbage was alive. In 1910, Henry Babbage, Charles Babbage's youngest son, was able to complete a portion of this machine and was able to perform basic calculations.

First programmable computer

The Z1 was created by German Konrad Zuse in his parents' living room between 1936and 1938. It is considered to be the first electro-mechanical binary programmable computer, and the first really functional modern computer.

First concepts of what we consider a modern computer

The Turing machine was first proposed by Alan Turing in 1936 and became the foundation for theories about computing and computers. The machine was a device that printed symbols on paper tape in a manner that emulated a person following a series of logical instructions. Without these fundamentals, we wouldn't have the computers we use today.

The first electric programmable computer

The Colossus was the first electric programmable computer, developed by Tommy Flowers, and first demonstrated in December1943. The Colossus was created to help the British code breakers read encrypted German messages.

The first digital computer

Short for Atanasoff-Berry Computer, theABC began development by Professor John Vincent Atanasoff and graduate student Cliff Berry in 1937. Its development continued until 1942 at the Iowa State College (now Iowa State University).

The ABC was an electrical computer that used vacuum tubes for digital computation, including binary math and Boolean logic and had no CPU. On October 19, 1973, the US Federal Judge Earl R. Larson signed his decision that the ENIAC patent by J. Presper Eckert and John Mauchly was invalid and named Atanasoff the inventor of the electronic digital computer.

The ENIAC was invented by J. Presper Eckert and John Mauchly at the University of Pennsylvania and began construction in 1943 and was not completed until 1946. It occupied about 1,800 square feet and used about 18,000 vacuum tubes, weighing almost 50 tons. Although the Judge ruled that the ABC computer was the first digital computer, many still consider the ENIAC to be the first digital computer because it was fully functional.

The first stored program computer

The early British computer known as the EDSAC is considered to be the first stored program electronic computer. The computer performed its first calculation on May 6,1949 and was the computer that ran the first graphical computer game, nicknamed "Baby".

      

Around the same time, the Manchester Mark 1 was another computer that could run stored programs. Built at the Victoria University of Manchester, the first version of the Mark 1 computer became operational in April 1949.  Mark 1 was used to run a program to search for Mersenne primes for nine hours without error on June 16 and 17 that same year.

The first computer company

The first computer company was the Electronic Controls Company and was founded in1949 by J. Presper Eckert and John Mauchly, the same individuals who helped create the ENIAC computer. The company was later renamed to EMCC or Eckert-Mauchly Computer Corporation and released a series of mainframe computers under the UNIVAC name.

First stored program computer

First delivered to the United States government in 1950, theUNIVAC 1101 or ERA 1101 is considered to be the first computer that was capable of storing and running a program from memory.

First commercial computer

In 1942, Konrad Zuse begin working on the Z4 that later became the first commercial computer. The computer was sold to Eduard Stiefel, a mathematician of the Swiss Federal Institute of Technology Zurich on July 12, 1950.

IBM's first computer

On April 7, 1953 IBM publicly introduced the 701; its first commercial scientific computer.

The first computer with RAM

MIT introduces the Whirlwind machine on March 8, 1955, a revolutionary computer that was the first digital computer with magnetic core RAM and real-time graphics.

The first transistor computer

The TX-O (Transistorized Experimental computer) is the first transistorized computer to be demonstrated at the Massachusetts Institute of Technology in1956.

The first minicomputer

In 1960, Digital Equipment Corporation released its first of many PDP computers, the PDP-1.

The first desktop and mass-market computer

In 1964, the first desktop computer, the Programma 101, was unveiled to the public at the New York World's Fair. It was invented by Pier Giorgio Perotto and manufactured by Olivetti. About 44,000 Programma 101 computers were sold, each with a price tag of $3,200.

In 1968, Hewlett Packard began marketing the HP 9100A, considered to be the first mass-marketed desktop computer.

The first workstation

Although it was never sold, the first workstation is considered to be the Xerox Alto, introduced in 1974. The computer was revolutionary for its time and included a fully functional computer, display, and mouse. The computer operated like many computers today utilizing windows, menus and icons as an interface to its operating system. Many of the computer's capabilities were first demonstrated in The Mother of All Demos byDouglas Engelbart on December 9, 1968.

The first microprocessor

Intel introduces the first microprocessor, the Intel 4004 on November 15, 1971.

The first micro-computer

The Vietnamese-French engineer, André Truong Trong Thi, along with Francois Gernelle, developed the Micral computer in 1973. Considered as the first "micro-computer", it used the Intel 8008 processor and was the first commercial non-assembly computer. It originally sold for $1,750.

The first personal computer

In 1975, Ed Roberts coined the term "personal computer" when he introduced the Altair8800. Although the first personal computer is considered by many to be the KENBAK-1, which was first introduced for $750 in 1971. The computer relied on a series of switches for inputting data and output data by turning on and off a series of lights.

The first laptop or portable computer

The IBM 5100 is the first portable computer, which was released on September 1975. The computer weighed 55 pounds and had a five inch CRT display, tape drive, 1.9MHz PALM processor, and 64KB of RAM. In the picture is an ad of the IBM 5100 taken from a November 1975 issue of Scientific America.

The first truly portable computer or laptop is considered to be the Osborne I, which was released on April 1981 and developed by Adam Osborne. The Osborne I weighed 24.5 pounds, had a 5-inch display, 64 KB of memory, two 5 1/4" floppy drives, ran theCP/M 2.2 operating system, included a modem, and cost US$1,795.

The IBM PC Division (PCD) later released the IBM portable in 1984, it's first portable computer that weighed in at 30 pounds. Later in 1986, IBM PCD announced it's firstlaptop computer, the PC Convertible, weighing 12 pounds. Finally, in 1994, IBM introduced the IBM ThinkPad 775CD, the first notebook with an integrated CD-ROM.

The first Apple computer

The Apple I (Apple 1) was the first Apple computer that originally sold for $666.66. The computer kit was developed by Steve Wozniak in 1976 and contained a 6502 8-bit processor and 4 kb of memory, which was expandable to 8 or 48 kb using expansion cards. Although the Apple I had a fully assembled circuit board the kit still required apower supply, display, keyboard, and case to be operational. Below is a picture of an Apple I from an advertisement by Apple.

The first IBM personal computer

IBM introduced its first personal computer called the IBM PC in 1981. The computer was code named and still sometimes referred to as the Acorn and had a 8088processor, 16 KB of memory, which was expandable to 256 and utilized MS-DOS.

The first PC clone

The Compaq Portable is considered to be the first PC clone and was release in March 1983 by Compaq. The Compaq Portable was 100% compatible with IBM computers and was capable of running any software developed for IBM computers.

• See the below other computer companies first for other IBM compatible computers

The first multimedia computer

In 1992, Tandy Radio Shack became one of the first companies to release a computer based on the MPC standard with its introduction of the M2500 XL/2 and M4020 SX computers.

Other computer company firsts

Below is a listing of some of the major computers companies first computers.

Commodore - In 1977, Commodore introduced its first computer, the "Commodore PET".
Compaq - In March 1983, Compaq released its first computer and the first 100% IBM compatible computer, the "Compaq Portable."
Dell - In 1985, Dell introduced its first computer, the "Turbo PC."
Hewlett Packard - In 1966, Hewlett Packard released its first general computer, the "HP-2115."
NEC - In 1958, NEC builds its first computer, the "NEAC 1101."
Toshiba - In 1954, Toshiba introduces its first computer, the "TAC" digital computer.

Additional information

• Who is the father of the computer?
• Computer history and timeline.
• How can I learn more about computers?
• See the computer definition for further information on computers and related links.

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From http://www.computerhope.com/issues/ch000984.htm
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