Software Engineering (SE) is the discipline of designing, creating, and maintaining software by applying technologies and practices from computer science, project management, engineering, application domains, interface design, digital asset management and other fields.

The term software engineering was popularized after 1968^[1], during the 1968 NATO Software Engineering Conference (held in Garmisch, Germany) by its chairman F.L. Bauer, and has been in widespread use since.

The term software engineering has been commonly used with a variety of distinct meanings:

• As the informal contemporary term for the broad range of activities that was formerly called programming and systems analysis;^[2]
• 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;^[3]
• 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 in the form of software engineering methodologies.^{[citation needed]}
• Software engineering is "(1) the application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software, that is, the application of engineering to software," and "(2) the study of approaches as in (1)." – IEEE Standard 610.12

Scope and Focus

Software engineering is concerned with the application of engineering principles to the conception, development and verification of a software system. This discipline deals with identifying, defining, realizing and verifying the required characteristics of the resultant software. These software characteristics may include: functionality, reliability, maintainability, availability, testability, ease-of-use, portability, and other attributes. Software engineering addresses these characteristics by preparing design and technical specifications that, if implemented properly, will result in software that can be verified to meet these requirements.

Software engineering is also concerned with the characteristics of the software development process. In this regard, it deals with characteristics such as cost of development, duration of development, and risks in development of software.

The Need for Software Engineering

Software is often found in products and situations where very high reliability is expected, even under demanding conditions, such as monitoring and controlling nuclear power plants, or keeping a modern airliner aloft^[4] Such applications contain millions of lines of code, making them comparable in complexity to the most complex modern machines. For example, a modern airliner has several million physical parts^[5] (and the space shuttle about ten million parts^[6]), while the software for such an airliner can run to 4 million lines of code^[7]. It would be impossible to manage the development, testing, and maintenance of such immense and complex software without the application of rigorous software engineering practices^{[citation needed]}.

See also List of software engineering topics (thematic) and List of software engineering topics (alphabetical).

Technologies and practices

Main article: Software development process

Software engineers advocate many different technologies and practices, with much disagreement. This debate has gone on for 60 years and may continue forever. Software engineers use a wide variety of technologies and practices. Practitioners use a wide variety of technologies: compilers, code repositories, word processors. Practitioners use a wide variety of practices to carry out and coordinate their efforts: pair programming, code reviews and daily stand up meetings.The goal of every software engineer should be to bring out an idea out of a previous planned modell and that which should be transparent and well documented( Omeke Tochukwu Benjamin(2006))

In spite of the enormous economic growth and productivity gains enabled by software, persistent complaints about the quality of software remain. Deficient software engineering is often blamed for project failures when the blame might more properly be placed with business managers who ignore lessons already learned by software engineers^{[citation needed]}.

See also: Debates within software engineering and Criticism of software engineering

What is the Nature of SE?

Software engineering resembles many different fields in many different ways. The following paragraphs make some simple comparisons.

Mathematics

Programs have many mathematical properties. For example the correctness and complexity of many algorithms are mathematical concepts that can be rigorously proven. Programs are finite, so in principle, developers could know many things about a program in a rigorous mathematical way. The use of mathematics within software engineering is often called formal methods. However, computability theory shows that not everything useful about a program can be proven. Mathematics works best for small pieces of code and has difficulty scaling up.

Engineering

Software Engineering is considered by many to be an engineering discipline because there are pragmatic approaches and expected characteristics of engineers. Proper analysis, documentation, and commented code are signs of an engineer. David Parnas has argued that software engineering is engineering^[8]. Programs have many properties that can be measured. For example, the performance and scalability of programs under various workloads can be measured. The effectiveness of caches, bigger processors, faster networks, newer databases are engineering issues. Mathematical equations can sometimes be deduced from the measurements. Mathematical approaches work best for system-wide analysis, but often are meaningless when comparing different small fragments of code.

Manufacturing

Programs are built in as a sequence of steps. By properly defining and carrying out those steps, much like a manufacturing assembly line, advocates hope to improve the productivity of developers and the quality of final programs. This approach inspires the many different processes and methodologies. While others, such as the authors of the Programmer's Stone, contend this view "[is] in fact claiming to be able to implement an Artificial Intelligence that simulates a production line designer"^[9].

Project management

Commercial (and many non-commercial) software projects require management. There are budgets and schedules to set. People to hire and lead. Resources (office space, computers) to acquire. All of this fits more appropriately within the purview of management.

Art

Programs contain many artistic elements, akin to writing or painting. User interfaces should be aesthetically pleasing to users. Code should be aesthetically pleasing to programmers. What is considered "good design" is usually subjective, and must be decided by one's own sense of aesthetics. Even the decision of whether a variable name or class name is clear and simple is an artistic question. Donald Knuth asserted that programming is an art.

Performance

The act of writing software requires that developers summon the energy to find the answers they need while they are at the keyboard. Creating software is a performance that resembles what athletes do on the field, and actors and musicians do on stage. Some argue that SEs need inspiration to spark the creation of code. Sometimes a creative spark is needed to create the architecture or to develop a unit of code to solve a particularly intractable problem. Others argue that discipline is the key attribute. Pair programming emphasizes this point of view. Both Kent Beck and Watts Humphrey have argued this emphasis. See also Performance Engineering.

Branch of Which Field?

Is SE (or should SE be) a branch of programming, a branch of computer science, a branch of traditional engineering, or a field that stands on its own? There is considerable debate over this. This has important implications for professionalism, licensing, and ethics. Licensing is a polarizing issue: some fiercely advocate it while others staunchly oppose it.

Branch of programming

Programming emphasizes writing code, independent of projects and customers. Software engineering emphasizes writing code in the context of projects and customers by making plans and delivering applications. As a branch of programming, SE would probably have no significant licensing or professionalism issues.

Branch of computer science

Many believe that software engineering is a part of computer science, because of their close historical connections and their relationship to mathematics. They advocate keeping SE a part of computer science. Both computer science and software engineering care about programs. Computer science emphasizes the theoretical, eternal truths while software engineering emphasizes practical, everyday usefulness. Some argue that computer science is to software engineering as physics and chemistry are to traditional engineering. As a branch of computer science, SE would probably have few licensing or professionalism concerns.

Branch of engineering

Some SE academics and practitioners, such as David Parnas^[10] and Steve McConnell^[11], have advocated treating SE an engineering discipline. Advocates for this view argue that the practice of engineering involves the use of mathematics, science, and the technology of the day, to build trustworthy products that are "fit for purpose", a description that applies as well to SE as to any other engineering discipline. As a branch of engineering, SE would probably adopt the engineering model of licensing and professionalism.

Freestanding field

Recently, software engineering has been finding its own identity and emerging as an important freestanding field^{[citation needed]}. Practitioners are slowly realizing that they form a huge community in their own right. Software engineering may need to create a form of regulation/licensing appropriate to its own circumstances^{[citation needed]}. It is arguable that licensing (in the United States) is inappropriate because the creation of software represents a form of writing, and requiring people to be licensed in order to write computer programs may be a violation of the First Amendment^{[citation needed]}. Requiring software engineers to be licensed by a government bureaucracy would make persons who create software without a license into criminals, even if they give their software away, same as practicing medicine or law without a license, even for free, is a criminal offense.

The U.S. Bureau of Labor Statistics classifies computer software engineers as a subcategory of "computer specialists", along with occupations such as computer scientist, programmer, and network administrator^[12]. The BLS classifies all other engineering disciplines, including computer hardware engineers, as "engineers"^[13].

The Software Engineering Profession

As of 2004, the U. S. Bureau of Labor Statistics counts 760,840 software engineers holding jobs in the U.S.; for comparison, in the U.S. there are some 1.4 million practitioners employed in all other engineering disciplines combined^[14]. There are estimated to be about 1.5 million practitioners in the E.U., Asia, and elsewhere^{[citation needed]}. SE pioneers include Barry Boehm, Fred Brooks, C. A. R. Hoare, and David Parnas. There is extensive debate about what SE is, who qualifies as a SE, who sets the standards, etc.

Debate over who is a software engineer

The use of "software engineer" as a corporate job title dates from at least 1990^{[citation needed]}. The person who has the job title "software engineer" and performs his job according to the job description for a "software engineer" is generally thought of as a software engineer. However, Bachelor's degrees in Software Engineering have become available from many well known universities. People who are from the outside of the corporate setting may believe that there are currently no widely accepted criteria for distinguishing someone who is a software engineer from someone who is not a software engineer. In addition, the industry is in the midst of a complex debate on the licensing of practicing software engineers. The two sides of the debate consider whether the job is a creative art or a repeatable science. In actual practice, the existing system of checking the work of the 'software engineer' when required by law by a state licensed professional engineer is considered adequate for legal liability reasons.

Debate over the term 'Engineering'

Some people believe that software development is a more appropriate term than software engineering for the process of creating software. Pete McBreen, (author of "Software Craftsmanship: The New Imperative" (ISBN 0-201-73386-2)), argues that the term Software Engineering implies levels of rigor and proven processes that are not appropriate for all types of software development. He argues strongly for 'craftsmanship' as a more appropriate metaphor because that term brings into sharper focus the skills of the developer as the key to success instead of the "manufacturing" process. Using a more traditional comparison, just as not everyone who works in construction is a civil engineer, not everyone who can write code is a software engineer.

Some people dispute the notion that the field is mature enough to warrant the title "engineering"^{[citation needed]}. Opposition also comes from the traditional engineering disciplines, whose practitioners usually object to the use of the title "engineer" by anyone who has not gone through an accredited program of engineering education^{[citation needed]}. In each of the last few decades, at least one radical new approach has entered the mainstream of software development (e.g. Structured Programming, Object Orientation, ... ), implying that the field is still changing too rapidly to be considered an engineering discipline. Other people would argue that the supposedly radical new approaches are actually evolutionary rather than revolutionary, the mere introduction of new tools rather than fundamental changes^{[citation needed]}.

Education

People from many different educational backgrounds make important contributions to SE. Today, software engineers earn software engineering, computer engineering or computer science degrees.

Software degrees

About half of all practitioners today have computer science degrees. A small, but growing, number of practitioners have software engineering degrees. In 1996, Rochester Institute of Technology established the first BSSE degree program in the United States but was beaten to ABET accreditation by Milwaukee School of Engineering. Both programs received ABET accreditation in 2003. Since then, software engineering undergraduate degrees have been established at many universities. A standard international curriculum for undergraduate software engineering degrees was recently defined by the CCSE. As of 2004, in the U.S., about 50 universities offer software engineering degrees, which teach both computer science and engineering principles and practices. The first graduate software engineering degree (MSSE) was established at Seattle University in 1979. Since then graduate software engineering degrees have been made available from many more universities.

Domain degrees

Some practitioners have degrees in application domains, bringing important domain knowledge and experience to projects. In MIS, some practitioners have business degrees. In embedded systems, some practitioners have electrical or computer engineering degrees, because embedded software often requires a detailed understanding of hardware. In medical software, some practitioners have medical informatics, general medical, or biology degrees.

Other degrees

Some practitioners have mathematics, science, engineering, or other technical degrees. Some have philosophy, or other non-technical degrees. And, some have no degrees. Note that Barry Boehm earned degrees in mathematics and Edsger Dijkstra earned degrees in physics.

Employment

See also: software engineering demographics

Most 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 required 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, managers) and in academia (educators, researchers).

There is considerable debate over the future employment prospects for Software Engineers and other IT Professionals. For example, an online futures market called the Future of IT Jobs in America attempts to answer whether there will be more IT jobs, including software engineers, in 2012 than there were in 2002.

Certification

Certification of software engineers is a contentious issue. Some see it as a tool to improve professional practice. Others point out that very few traditional engineers bother with any form of certification.

Most successful certification programs in the software industry are oriented toward specific technologies, and are managed by the vendors of these technologies. These certification programs are tailored to the institutions that would employ people who use these technologies. General certification of software practitioners has struggled. The ACM had a professional certification program in the early 1980s, which was discontinued due to lack of interest. Today, the IEEE is certifying software professionals, but only about 500 people have passed the exam by March 2005. In Canada the use of the title of Software Engineer is regulated^{[citation needed]}, and Information Systems Professional certification is used.

For the localities that do not license or certify software engineers, some hiring classifications are made based on education and experience. Classification levels may include: entry-level, mid-level, and senior. Typical entry-level software engineers have a bachelor's degree and zero to five years of experience. Typical mid-level software engineers have a bachelor's or master's degree and have five to ten years of experience. Typical senior-level software engineers have an advanced degree and have ten or more years of experience. Note that these are only guidelines that are trends seen in hiring practices^{[citation needed]} and that many exceptions exist.

Impact of Globalization

Many students in the developed world have avoided degrees 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 [1]. Although government statistics do not currently show a threat to software engineering itself; a related career, computer programming does appear to have been affected [2]. Often one is expected to start out as a computer programmer before being promoted to software engineer. Thus, the career path to software engineering may be rough, especially during recessions.

Some career counselors suggest a student also focus on "people skills" and business skills rather than purely technical skills because such "soft skills" are allegedly more difficult to offshore [3]. It is the quasi-management aspects of software engineering that appear to be what has kept it from being impacted by globalization. [4]

Comparing related fields

Main article: Comparing software engineering and related fields

Many fields are closely related to software engineering; here are some key similarities and distinctions. Comparing SE with other fields helps explain what SE is and helps define what SE might or should become. There is considerable debate over which fields SE most resembles (or should most resemble). These complex and inexact comparisons explain why some see software engineering as its own field.

History

Main article: History of software engineering

Software engineering has a long evolving history. Both the tools that are used and the applications that are written have evolved over time. It seems likely that software engineering will continue evolving for many decades to come.

60 year time line

• 1940s: First computer users wrote machine code by hand^{[citation needed]}.
• 1950s: Early tools, such as macro assemblers and interpreters were created and widely used to improve productivity and quality^{[citation needed]}. First generation optimizing compilers^{[citation needed]}.
• 1960s: Second generation tools like optimizing compilers and inspections were being used to improve productivity and quality^{[citation needed]}. The concept of software engineering was widely discussed^{[citation needed]}. First really big (1000 programmer) projects^{[citation needed]}. Commercial mainframes and custom software for big business. The influential 1968 NATO Conference on Software Engineering was held.
• 1970s: Collaborative software tools, such as Unix, code repositories, make, and so on. Minicomputers and the rise of small business software.
• 1980s: Personal computers and personal workstations become common. Commensurate rise of consumer software.
• 1990s: Object-oriented programming and agile processes like Extreme programming gain mainstream acceptance^{[citation needed]}. The WWW and hand-held computers make software even more widely available.
• 2000s: Managed code and interpreted platforms such as .NET, PHP, Python and Java make writing software easier than ever before^{[citation needed]}.

Current trends in software engineering

Software engineering is a young discipline, and is still developing. The directions in which software engineering is developing include:

Aspects

Aspects help programmers deal with -ilities by providing tools to add or remove boilerplate code from many areas in the source code. Aspects describe how all objects or functions should behave in particular circumstances. For example, aspects can add debugging, logging, or locking control into all objects of particular types. Researchers are currently working to understand how to use aspects to design general-purpose code. Related concepts include generative programming and templates.

Agile

Agile software development guides software development projects that evolve rapidly with changing expectations and competitive markets. Proponents of agile software development believe that heavy, document-driven processes (like TickIT, CMM and ISO 9000) are fading in importance^{[citation needed]}. Some people believe that companies and agencies export many of the jobs that can be guided by heavy-weight processes^{[citation needed]}. Related concepts include extreme programming and lean software development.

Experimental

Experimental software engineering is a branch of software engineering interested in devising experiments on software, in collecting data from these experiments, and in devising laws and theories from this data. Proponents of experimental software engineering advocate that the nature of software is such that we can advance the knowledge on software through experiments only^{[citation needed]}.

Software Product Lines

Software Product Lines is a systematic way of producing families of software systems, instead of creating a succession of completely individual products. The Software Product Lines approach is an attempt to industrialize the software development process.

The Future of Software Engineering conference (FOSE), held at ICSE 2000, documented the state of the art of SE in 2000 and listed many problems to be solved over the next decade. The Feyerabend project attempts to discover the future of software engineering by seeking and publishing innovative ideas.

Software engineering today

In 2006, Money Magazine and Salary.com rated software engineering as the best job in America in terms of growth, pay, stress levels, flexibility in hours and working environment, creativity, and how easy it is to enter and advance in the field^[15].

See also software engineering economics.

Conferences, organizations and publications

Conferences

Several academic conferences devoted to software engineering are held every year. There are also many other academic conferences every year devoted to special topics within SE, such as programming languages, requirements, testing, and so on.

ICSE

The biggest and oldest conference devoted to software engineering is the International Conference on Software Engineering. This conference meets every year to discuss improvements in research, education, and practice.

COMPSAC

The Annual International Computer Software and Applications Conference was first held in Chicago in 1977 and is designated as the IEEE Computer Society signature conference on software technology and applications.

ESEC

The European Software Engineering Conference.

FSE

The Foundations of Software Engineering conference is held every year, alternating between Europe and North America. It emphasizes theoretical and foundational issues.

CUSEC

Conferences dedicated to inform undergraduate students like the annual Canadian University Software Engineering Conference are also very promising for the future generation. It is completely organized by undergraduate students and lets different Canadian universities interested in Software Engineering host the conference each year. Past guests include Kent Beck, Joel Spolsky, Philippe Kruchten, Hal Helms, Craig Larman, David Parnas as well as university professors and students.

SEPG

The annual Software Engineering Process Group conference, sponsored by the Carnegie Mellon Software Engineering Institute (SEI), is a conference and exhibit showcase for systems and software engineering professionals. The four-day event emphasizes systematic improvement of people, processes, and technology.

INFORMATICS-INFORMATIQUE

The annual Canadian information technology, data processing and software engineering symposium, sponsored by the Canadian Information Processing Society. First held in 1958.

ICALEPS

International Conference on Accelerator and Large Experimental Physics Control Systems Conference [5]. Biennial conference covering software engineering for large scale scientific control systems. First held in 1987.

APSEC

Asia Pacific Software Engineering Conference [6].

Organizations

• Association for Computing Machinery (ACM)
• British Computer Society (BCS)
• Australian Computer Society (ACS)
• Canadian Information Processing Society (CIPS) - Information Systems Professional certification.
• IEEE Computer Society
• Lero, the Irish Software Engineering Research Centre
• RUSSOFT Association
• Software Engineering Institute (SEI)

Publications

• Important publications in software engineering

References

External links

• Computer Software Engineers - Definition and statistics from the U.S. Bureau of Labor Statistics
• Belief that title "engineering" is inappropriate
• Quotation from IEEE Std 610-1990
• Is software engineering actually engineering?: The "yes" point of view
• Is software development engineering?: Another "yes" point of view
• Top Ten Myths about Software Engineering
• Big Ball of Mud A "yes but why not" point of view by Brian Foote and Joseph Yoder, Department of Computer Science, University of Illinois at Urbana-Champaign
• Scientific American Magazine (June 2006 Issue) Dependable Software by Design
• Guide to the Software Engineering Body of Knowledge