Software engineering (SE) is the profession concerned with creating and maintaining software applications by applying computer science, project management, domain knowledge, and other skills and technologies.
Software applications (including ATMs, compilers, databases, email, embedded systems, graphics, office suites, operating systems, robotics, video games, and the world wide web) embody social and economic value, by making people more productive, improving their quality of life, and enabling them to do things that would otherwise be impossible. SE technologies and practices (including databases, languages, libraries, patterns, platformss, processes, standards, and tools) help developers, by improving productivity and quality.
The SE community includes 630,000 practitioners and educators in the U.S and an estimated 1,400,000 practitioners in the E.U, Asia, and elsewhere; and is about 60% the size of traditional engineering. American SE pioneers include Kent Beck, Barry Boehm, Fred Brooks, Watts Humphrey, and David Parnas.
There is considerable debate over whether software development should be considered a branch of traditional engineering, a branch of computer science, an independent scientific field, or a non-scientific craft. This article attempts to be neutral on this issue, but errs on the side of being independent to clarify the differences between fields.
As of 2004, in common parlance the term software engineering is used with at least three distinct meanings:
- As the usual contemporary term for the broad range of activities that was formerly called programming or systems analysis;
- As the broad term for the technical analysis of all aspects of the practice, as opposed to the theory of computer programming;
- As the term embodying the advocacy of a specific approach to computer programming, one that urges that it be treated as an engineering profession rather than an art or a craft, and advocates the codification of recommended practices in the form of software engineering methodologies.
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Software Engineering matters
In the U.S., software drove about 1/4 of all increase in GDP during the 1990s (about $90 billion per year), and 1/6 of all productivity growth (efficiency within GDP) during the late 1990s (about $33 billion per year). Software engineering drove $1 trillion of economic and productivity growth over the last decade. See also software engineering economics.
Software engineering changes world culture, wherever people use computers. Email, the world-wide web, and instant messaging enable people to interact in new ways. Software lowers the cost and improves the quality of health-care, fire departments, and other important social services.
Successful projects where software engineering methods have been applied include Linux, the space shuttle software, and automatic teller machines. When it is cheaper to run a business or agency with software applications than without, businesses and agencies often invest in computers, software, and personnel.
People from many different educational backgrounds make important contributions to SE. The fraction of practitioners who earn computer science or software engineering degrees has been slowly rising. Today about 1/2 of all software engineers earn computer science or software engineering degrees. For comparison, about 3/4 of all traditional engineers earn engineering degrees.
Software: About half of all practitioners today have computer science degrees, which are the most relevant degrees that are widely available. A small, but growing, number of practitioners have software engineering degrees. Today in the U.S., about 2,000 universities offer computer science degrees and about 50 universities offer software engineering degrees. Most SE practitioners will earn computer science degrees for decades to come, though someday, this may change.
Domain: 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 degrees, or general medical or biology degrees.
Other: 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.
Graduate software engineering degrees have been available from dozens of universities for a decade or so. Undergraduate software engineering degrees are being established at many universities. A new curriculum for undergraduate software engineering degrees is currently being defined by the CCSE.
Most software engineers work as employees or contractors. Software engineers work with businesses, government agencies (civilian or military), and non-profit agencies (a school or .org like Wikipedia). Some software engineers work for themselves as free agents.
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 the question as to whether there will be more IT jobs, including software engineers, in 2012 than there were in 2002.
Many debates are raging within SE. As software becomes more pervasive, we all recognize the need for better software, but we disagree on how.
Technologies and Practices: What is the best way to make more and better software? SEs advocate many different technologies and practices, with much disagreement. This debate has gone on for 60 years and may continue forever.
Identity: Is SE a branch of computer science, a branch of traditional engineering, or a field that stands on its own? Recently, software engineering has been finding its own identity and emerging as an important field. Yet, some advocate making SE a part of traditional engineering and others advocate keeping SE a part of computer science.
Professionalism: What will SEs do about professionalism, licensing, and ethics? Licensing is a polarizing issue. Some fiercely advocate it. Others staunchly oppose it.
Success: Is SE a success or a failure? Some look to the enormous economic growth and productivity gains enabled by software and claim that software engineering is a huge success. Others point to the ongoing problems with crashing operating systems and computer viruses and claim that software engineering has failed. How can we reconcile these points of view?
For more details see Debates within software engineering.
Current directions for software engineering
Aspect-oriented programming and agile methods are important emerging SE technologies and practices.
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, aspectss 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 Methods guide software development projects that evolve rapidly with changing expectations and competitive markets. The heavy, document-driven processes (like CMM and ISO 9000) are fading in importance. Some people believe that companies and agencies export many of the jobs that can be guided by heavy-weight processes. Related concepts include extreme programming and lean software development.
The Future of Software Engineering conference (FOSE) held at the 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.