is the application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software
. It encompasses techniques and procedures, often regulated by a software development process
, with the purpose of improving the reliability and maintainability of software systems. The effort is necessitated by the potential complexity of those systems, which may contain millions of lines of code
The term software engineering
was coined by F.L. Bauer
and popularized by the 1968 NATO Software Engineering Conference, which was organized by Brian Randell
The discipline of software engineering includes knowledge, tools, and methods for software requirements, software design, software construction, software testing, and software maintenance tasks. Software engineering is related to the disciplines of computer science, computer engineering, management, mathematics, project management, quality management, software ergonomics, and systems engineering.
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. 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 as a result most software engineers hold computer science degrees. The term software engineer is used very liberally in the corporate world. Very few of the practicing software engineers actually hold Engineering degrees from accredited universities. In fact, according to the Association for Computing Machinery, "most people who now function in the U.S. as serious software engineers have degrees in computer science, not in software engineering".
Ambiguity and controversy
Typical formal definitions of software engineering are:
- "the application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software".
- "an engineering discipline that is concerned with all aspects of software production"
- "the establishment and use of sound engineering principles in order to economically obtain software that is reliable and works efficiently on real machines"
The term has been used less formally:
- as the informal contemporary term for the broad range of activities that were formerly called programming and systems analysis;
- 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;
- 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.
Some people believe that software engineering implies a certain level of academic training, professional discipline, and adherence to formal processes that often are not applied in cases of software development. A common analogy is that working in construction does not make one a civil engineer, and so writing code does not make one a software engineer. It is disputed by some - in particular by the Canadian Professional Engineers Ontario (PEO) body, that the field is not mature enough to warrant the title "engineering". The PEO disputed that "software engineering" was not an appropriate name for the field since those who practiced in the field and called themselves "software engineers" were not properly licensed professional engineers, and that they should therefore not be allowed to use the name.
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. Proponents argue that the supposedly radical new approaches are evolutionary rather than revolutionary.
Individual commentators have disagreed sharply on how to define software engineering or its legitimacy as an engineering discipline. David Parnas has said that software engineering is, in fact, a form of engineering. Steve McConnell has said that it is not, but that it should be. Donald Knuth has said that programming is an art and a science. Edsger W. Dijkstra claimed that the terms software engineering and software engineer have been misused, particularly in the United States.
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. The BLS classifies all other engineering disciplines, including computer hardware engineers, as "engineers".
The U.K. has seen the alignment of the Information Technology Professional and the Engineering Professionals.
Software engineering in Canada has seen some contests in the courts over the use of the title "Software Engineer The Canadian Council of Professional Engineers (C.C.P.E. or "Engineers Canada") will not grant a "Professional Engineer" status/license to anyone who has not completed a recognized academic engineering program. Engineers qualified outside Canada are similarly unable to obtain a "Professional Engineer" license. Since 2001, the Canadian Engineering Accreditation Board has accredited several university programs in software engineering, allowing graduates to apply for a professional engineering licence once the other prerequisites are obtained, although this does nothing to help IT professionals using the title with degrees in other fields (such as computer science).
Some of the United States of America regulate the use of terms such as "computer engineer" and even "software engineer". These states include at least Texas and Florida. Texas even goes so far as to ban anyone from writing any real-time code without an engineering license.
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.
- 1950s: Early tools, such as macro assemblers and interpreters were created and widely used to improve productivity and quality. First-generation optimizing compilers.
- 1960s: Second generation tools like optimizing compilers and inspections were being used to improve productivity and quality. The concept of software engineering was widely discussed. First large scale(1000 programmer) projects. 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 became common. Commensurate rise of consumer software. Smalltalk: the first commercial OOP language/platform that is UI based, Memory Managed, VM Image based, scripted/incremental.
- 1990s: Object-oriented programming and agile processes like Extreme programming gained mainstream acceptance. Computer memory capacity sky-rocketed and prices dropped drastically. These new technologies allowed software to grow more complex. The WWW and hand-held computers made software even more widely available.
- 2000s: Managed code and interpreted platforms such as Java, .NET, Ruby, Python and PHP made writing software easier than ever before. Offshore outsourcing changed the nature and focus of software engineering careers.
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 software engineers deal with quality attributes
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
, 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
. Agile: Agile software development
guides software development
projects that evolve rapidly with changing expectations
and competitive markets. Proponents of this method believe that heavy, document-driven processes (like TickIT
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
. Experimental: Experimental software engineering
is a branch of software engineering interested in devising experiments
on software, in collecting data from the experiments, and in devising laws and theories from this data. Proponents of this method advocate that the nature of software is such that we can advance the knowledge on software through experiments only. Model-driven: Model Driven Design
develops textual and graphical models as primary design artifacts. Development tools are available that use model transformation
and code generation
to generate well-organized code fragments that serve as a basis for producing complete applications. Software Product Lines: Software Product Lines
is a systematic way to produce families
of software systems, instead of creating a succession of completely individual products. This method emphasizes extensive, systematic, formal code reuse
, to try 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 FOSE tracks at the ICSE 2000 and the ICSE 2007 conferences also help identify the state of the art in software engineering.
Software engineering today
The profession is trying to define its boundary and content. The Software Engineering Body of Knowledge SWEBOK
has been tabled as an ISO standard during 2006 (ISO/IEC TR 19759).
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.
About half of all practitioners today have computer science degrees
. A small, but growing, number of practitioners have software engineering degrees
. In 1987 Imperial College London
introduced the first three year software engineering Bachelor's degree
in the UK and the world, in the following year the University of Sheffield
established a similar programme. In 1996, Rochester Institute of Technology
established the first software engineering Bachelor's degree
program in the United States, however, it did not obtain ABET
until 2003, the same time as Clarkson University
, Milwaukee School of Engineering
and Mississippi State University
. 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 software engineering Master's degree
was established at Seattle University
in 1979. Since then graduate software engineering degrees have been made available from many more universities. Likewise in Canada, the Canadian Engineering Accreditation Board (CEAB) of the Canadian Council of Professional Engineers
has recognized software engineering programs in engineering faculties such as McMaster University
, the University of Waterloo
, the University of Ottawa
and the University of Western Ontario
, the University of Calgary
, the University of Victoria
, École Polytechnique de Montréal
, McGill University
the ETS in Montréal and the Université Laval
In 1998, the US Naval Postgraduate School (NPS) established the first doctorate program in Software Engineering in the world. As of the beginning of 2006, thirteen students had graduated from the program and assumed senior-level leadership roles in the Department of Defense research and development community. Additionally, many online advanced degrees in Software Engineering have appeared such as the Master of Science in Software Engineering (MSE) degree offered through the Computer Science and Engineering Department at California State University, Fullerton.
Steve McConnell opines that because most universities teach computer science rather than software engineering, there is a shortage of true software engineers.
ETS University and UQAM were mandated by IEEE to develop the SoftWare Engineering BOdy of Knowledge SWEBOK, which has become an ISO standard describing the body of knowledge covered by a software engineer .
In business, some software engineering practitioners have MIS
degrees. In embedded systems
, some have electrical
or computer engineering
degrees, because embedded software often requires a detailed understanding of hardware. In medical software, practitioners may have medical informatics
, general medical, or biology degrees.
Some practitioners have mathematics, science, engineering, or technology degrees. Some have philosophy (logic in particular) or other non-technical degrees. And, others have no degrees. For instance, Barry Boehm earned degrees in mathematics.
- 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.
Professional certification of software engineers is a contentious issue. Some see it as a tool to improve professional practice.
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.
The ACM had a professional certification program in the early 1980s, which was discontinued due to lack of interest.. As of 2006, the IEEE had certified over 575 software professionals. In Canada the Canadian Information Processing Society has developed a legally recognized professional certification called Information Systems Professional (ISP).
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. Although government statistics do not currently show a threat to software engineering itself; a related career, computer programming does appear to have been affected. 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. It is the quasi-management aspects of software engineering that appear to be what has kept it from being impacted by globalization.
Comparing 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.
- Main lists: List of basic software engineering topics and List of software engineering topics
- Jalote, Pankaj (2005). >An Integrated Approach to Software Engineering. 3th ed., : Springer.
- Sommerville, Ian (2007). >Software Engineering. 8th ed., Harlow, England: Pearson Education.
- Pressman, Roger S (2005). Software Engineering: A Practitioner's Approach. 6th ed., Boston, Mass: McGraw-Hill.
- Carlo Ghezzi, Mehdi Jazayeri, Dino Mandrioli: Fundamentals of Software Engineering, 2nd (International) ed.: 2003 (1st ed.: 1991), Pearson Education @ Prentice-Hall
- Colin Hood,Simon Wiedemann, Stefan Fichtinger, Urte Pautz Requirements Management: Interface Between Requirements Development and All Other Engineering Processes Springer, Berlin 2007, ISBN 354047689X