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Software engineering

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Software engineering (SE) is the profession of people who create and maintain software applications by applying technologies and practices from computer science, project management, engineering, application domains and other fields.

Software engineering deals with matters of cost and reliability, like traditional engineering disciplines. Some software applications contain millions of lines of code that are expected to perform properly in the face of changing conditions, making them comparable in complexity to the most complex modern machines. For example, a modern airliner has several million physical parts[1] (and the space shuttle about ten million parts[2]), while the software for such an airliner can run to 4 million lines of code[3].

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[4]. 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.

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

Contents

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Terminology

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Origins

The term software engineering was used occasionally in the late 1950s and early 1960s. It was popularized during the 1968 NATO Software Engineering Conference (held in Garmisch, Germany) by its chairman F.L. Bauer, and has been in widespread use since.

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Meanings

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

  • As the usual contemporary term for the broad range of activities that was 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 profession rather than an art or a craft, and advocates the codification of recommended practices in the form of software engineering methodologies.
  • 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

Software engineering is practiced by software engineers.

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Debate over who is a software engineer

Some people believe that software development is a more appropriate term than software engineering for the process of creating software. People like Pete McBreen (author of "Software Craftsmanship: The New Imperative" (ISBN 0-201-73386-2)) believe that the term Software Engineering implies levels of rigor and proven processes that are not appropriate for all types of software development. McBreen goes on to make a strong case for craftsmanship as a more appropriate metaphor because it focuses on the skills of the developer as the key to success instead of the "manufacturing" process.

Some people dispute the notion that the field is mature enough to warrant the title "engineering". Additional opposition 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 based on mathematics and the physical sciences. 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.

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. Furthermore, software engineering can be viewed as an art rather than a science taking from the realm of state licensing. Moreover, software engineer is a corporate job title which has been around since at least 1990. Recently, bachelor's degrees in Software Engineering have become available from many well known universities.

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. The title of engineer can only be granted by a professional association.

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Software engineering today

Software engineering affects culture and society in many ways.

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[5].

See also software engineering economics.

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Technologies and practices

Main article: Software development process

What is the best way to make more and better software? 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, to 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.

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.

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Education

A fellow editor requested that someone provide references or some sources for the information in this section.

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.
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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.

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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.

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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.

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What is the nature of SE?

A fellow editor requested that someone provide references or some sources for the information in this section.

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. Edsger Dijkstra has argued that software engineering is a branch of mathematics.
Science
Programs have many scientific 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 scientific issues. Mathematical equations can sometimes be deduced from the measurements. Scientific approaches work best for system-wide analysis, but often are meaningless when comparing different small fragments of code.
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[6].
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"[7].
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 famously argued 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.
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Branch of which field?

A fellow editor requested that someone provide references or some sources for the information in this section.

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[8] and Steve McConnell[9], 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 dicsipline. 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. 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. 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. Requiring software engineers to be licensed 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. It could also be argued the requirement of licensing of programmers could be "prostituted" into an orthodoxy where those who create software in ways or using methods which are not approved by the licensing authorities may be subject to sanctions up to and including loss of license. Thus the licensing authorities could conceivably hold people to whatever "flavor of the month" of software engineering standards are considered a good idea at that time, under threat of loss of livelihood.

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[10]. The BLS classifies all other engineering disciplines, including computer hardware engineers, as "engineers"[11].

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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.

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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 really big (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 workstations and an emphasis on process like the CMM. The rise of consumer software.
  • 1990s: Object-oriented programming and agile processes like Extreme programming gain mainstream acceptance. The WWW and hand-held computers make software even more widely available.
  • 2000s: Managed and interpreted platforms such as .NET, PHP, Python and Java make writing software easier than ever before[citation needed].
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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. Proponent 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.

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Conferences, organizations and publications

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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, 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 [1]. Biennial conference covering software engineering for large scale scientific control systems. First held in 1987.
APSEC
Asia Pacific Software Engineering Conference [2].
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Organizations

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Publications


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External links

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References

  1. ^ Boeing 747, By the Numbers "Six million: the number of parts, half of which are fasteners."
  2. ^ Grübler, Arnulf (2003). Technology and Global Change. Cambridge University Press. ISBN 0521543320. p. 33: "A Boeing 747 [contains] roughly 3.5 million [parts]... the apogee (and nightmare) of mechanical complexity is the space shuttle, with 10 million parts."
  3. ^ Pehrson, Ronald J. (January 1996). "Software Development for the Boeing 777". CrossTalk: The Journal of Defense Software Engineering., "The 2.5 million lines of newly developed software were approximately six times more than any previous Boeing commercial airplane development program. Including commercial-off-the-shelf (COTS) and optional software, the total size is more than 4 million lines of code."
  4. ^ Bureau of Labor Statistics, U.S. Department of Labor, USDL 05-2145: Occupational Employment and Wages, November 2004, Table 1.
  5. ^ Kalwarski, Tara; Daphne Mosher, Janet Paskin and Donna Rosato (2006). "Best Jobs in America." MONEY Magazine. CNN. URL accessed on 2006-04-20., "MONEY Magazine and Salary.com researched hundreds of jobs, considering their growth, pay, stress-levels and other factors. These careers ranked highest. 1. Software Engineer..."
  6. ^ Parnas, David L. (1998). "Software Engineering Programmes are not Computer Science Programmes". Annals of Software Engineering 6: 19–37., p. 19: "Rather than treat software engineering as a subfield of computer science, I treat it as an element of the set, {Civil Engineering, Mechanical Engineering, Chemical Engineering, Electrical Engineering,....}."
  7. ^ Carter, A.G.; C. Sanger (1997). "Thinking About Thinking." The Programmers' Stone. Alan Carter. URL accessed on 2006-05-13.
  8. ^ Parnas, David L. (1998). "Software Engineering Programmes are not Computer Science Programmes". Annals of Software Engineering 6: 19–37., p. 20: "This paper argues that the introduction of accredited professional programmes in software engineering, programmes that are modelled on programmes in traditional engineering disciplines will help to increase both the quality and quantity of graduates who are well prepared, by their education, to develop trustworthy software products."
  9. ^ McConnell, Steve (August 2003). Professional Software Development: Shorter Schedules, Better Projects, Superior Products, Enhanced Careers. Boston, MA: Addison-Wesley. ISBN 0321193679., p. 39: "In my opinion, the answer to that question is clear: Professional software development should be engineering. Is it? No. But should it be? Unquestionably, yes. "
  10. ^ U.S Department of Labor and Statistics The 2000 Standard Occupational Classification (SOC) System: 15-0000 Computer and Mathematical Occupations
  11. ^ U.S Department of Labor and Statistics The 2000 Standard Occupational Classification (SOC) System: 17-0000 Architecture and Engineering Occupations
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