Showing posts with label Computer program. Show all posts
Showing posts with label Computer program. Show all posts

Friday, December 3

Computer software

Computer software, or just software, is the collection of computer programs and related data that provide the instructions telling a computer what to do. We can also say software refers to one or more computer programs and data held in the storage of the computer for some purposes. Program software performs the function of the program it implements, either by directly providing instructions to the computer hardware or by serving as input to another piece of software. The term was coined to contrast to the old term hardware (meaning physical devices). In contrast to hardware, software is intangible, meaning it "cannot be touched". Software is also sometimes used in a more narrow sense, meaning application software only. Sometimes the term includes data that has not traditionally been associated with computers, such as film, tapes, and records.
Examples of computer software include:
Application software includes end-user applications of computers such as word processors or video games, and ERP software for groups of users.
Middleware controls and co-ordinates distributed systems.
Programming languages define the syntax and semantics of computer programs. For example, many mature banking applications were written in the COBOL language, originally invented in 1959. Newer applications are often written in more modern programming languages.
System software includes operating systems, which govern computing resources. Today large applications running on remote machines such as Websites are considered to be system software, because the end-user interface is generally through a graphical user interface, such as a web browser.
Testware is software for testing hardware or a software package.
Firmware is low-level software often stored on electrically programmable memory devices. Firmware is given its name because it is treated like hardware and run ("executed") by other software programs.
Shrinkware is the older name given to consumer-purchased software, because it was often sold in retail stores in a shrink-wrapped box.
Device drivers control parts of computers such as disk drives, printers, CD drives, or computer monitors.
Programming tools help conduct computing tasks in any category listed above. For programmers, these could be tools for debugging or reverse engineering older legacy systems in order to check source code compatibility.


History

For the history prior to 1946, Read More: History of computing hardware.
The first theory about software was proposed by Alan Turing in his 1935 essay Computable numbers with an application to the Entscheidungsproblem (Decision problem). The term "software" was first used in print by John W. Tukey in 1958. Colloquially, the term is often used to mean application software. In computer science and software engineering, software is all information processed by computer system, programs and data. The academic fields studying software are computer science and software engineering.
The history of computer software is most often traced back to the first software bug in 1946. As more and more programs enter the realm of firmware, and the hardware itself becomes smaller, cheaper and faster due to Moore's law, elements of computing first considered to be software, join the ranks of hardware. Most hardware companies today have more software programmers on the payroll than hardware designers, since software tools have automated many tasks of Printed circuit board engineers. Just like the Auto industry, the Software industry has grown from a few visionaries operating out of their garage with prototypes. Steve Jobs and Bill Gates were the Henry Ford and Louis Chevrolet of their times, who capitalized on ideas already commonly known before they started in the business. In the case of Software development, this moment is generally agreed to be the publication in the 1980s of the specifications for the IBM Personal Computer published by IBM employee Philip Don Estridge. Today his move would be seen as a type of crowd-sourcing.


Until that time, software was bundled with the hardware by Original equipment manufacturers (OEMs) such as Data General, Digital Equipment and IBM. When a customer bought a minicomputer, at that time the smallest computer on the market, the computer did not come with Pre-installed software, but needed to be installed by engineers employed by the OEM. Computer hardware companies not only bundled their software, they also placed demands on the location of the hardware in a refrigerated space called a computer room. Most companies had their software on the books for 0 dollars, unable to claim it as an asset (this is similar to financing of popular music in those days). When Data General introduced the Data General Nova, a company called Digidyne wanted to use its RDOS operating system on its own hardware clone. Data General refused to license their software (which was hard to do, since it was on the books as a free asset), and claimed their "bundling rights". The Supreme Court set a precedent called Digidyne v. Data General in 1985. The Supreme Court let a 9th circuit decision stand, and Data General was eventually forced into licensing the Operating System software because it was ruled that restricting the license to only DG hardware was an illegal tying arrangement. Soon after, IBM 'published' its DOS source for free, and Microsoft was born. Unable to sustain the loss from lawyer's fees, Data General ended up being taken over by EMC Corporation. The Supreme Court decision made it possible to value software, and also purchase Software patents. The move by IBM was almost a protest at the time. Few in the industry believed that anyone would profit from it other than IBM (through free publicity). Microsoft and Apple were able to thus cash in on 'soft' products. It is hard to imagine today that people once felt that software was worthless without a machine. There are many successful companies today that sell only software products, though there are still many common software licensing problems due to the complexity of designs and poor documentation, leading to patent trolls.
With open software specifications and the possibility of software licensing, new opportunities arose for software tools that then became the de facto standard, such as DOS for operating systems, but also various proprietary word processing and spreadsheet programs. In a similar growth pattern, proprietary development methods became standard Software development methodology.

Overview
A layer structure showing where operating system is located on generally used software systems on desktops
Software includes all the various forms and roles that digitally stored data may have and play in a computer (or similar system), regardless of whether the data is used as code for a CPU, or other interpreter, or whether it represents other kinds of information. Software thus encompasses a wide array of products that may be developed using different techniques such as ordinary programming languages, scripting languages, microcode, or an FPGA configuration.
The types of software include web pages developed in languages and frameworks like HTML, PHP, Perl, JSP, ASP.NET, XML, and desktop applications like OpenOffice.org, Microsoft Word developed in languages like C, C++, Java, C#, or Smalltalk. Application software usually runs on an underlying software operating systems such as Linux or Microsoft Windows. Software (or firmware) is also used in video games and for the configurable parts of the logic systems of automobiles, televisions, and other consumer electronics.
Computer software is so called to distinguish it from computer hardware, which encompasses the physical interconnections and devices required to store and execute (or run) the software. At the lowest level, executable code consists of machine language instructions specific to an individual processor. A machine language consists of groups of binary values signifying processor instructions that change the state of the computer from its preceding state. Programs are an ordered sequence of instructions for changing the state of the computer in a particular sequence. It is usually written in high-level programming languages that are easier and more efficient for humans to use (closer to natural language) than machine language. High-level languages are compiled or interpreted into machine language object code. Software may also be written in an assembly language, essentially, a mnemonic representation of a machine language using a natural language alphabet. Assembly language must be assembled into object code via an assembler.

Types of software

Practical computer systems divide software systems into three major classes: system software, programming software and application software, although the distinction is arbitrary, and often blurred.

System software
System software provides the basic functions for computer usage and helps run the computer hardware and system. It includes a combination of the following:
device drivers
operating systems
servers
utilities
window systems
System software is responsible for managing a variety of independent hardware components, so that they can work together harmoniously. Its purpose is to unburden the application software programmer from the often complex details of the particular computer being used, including such accessories as communications devices, printers, device readers, displays and keyboards, and also to partition the computer's resources such as memory and processor time in a safe and stable manner.

Programming software
Programming software usually provides tools to assist a programmer in writing computer programs, and software using different programming languages in a more convenient way. The tools include:
compilers
debuggers
interpreters
linkers
text editors
An Integrated development environment (IDE) is a single application that attempts to manage all these functions.

Application software
System software does not aim at a certain application fields.In contrast,different application software offers different function based on users and the area it served.Application software is developed for some certain purpose,which either can be a certain program or a collection of some programmes,such as a graphic browser or the data base management system. Application software allows end users to accomplish one or more specific (not directly computer development related) tasks. Typical applications include:
industrial automation
business software
video games
quantum chemistry and solid state physics software
telecommunications (i.e., the Internet and everything that flows on it)
databases
educational software
Mathematical software
medical software
molecular modeling software
image editing
spreadsheet
simulation software
Word processing
Decision making software
Application software exists for and has impacted a wide variety of topics.

Software topics

Software architecture
Users often see things differently than programmers. People who use modern general purpose computers (as opposed to embedded systems, analog computers and supercomputers) usually see three layers of software performing a variety of tasks: platform, application, and user software.
Platform software: Platform includes the firmware, device drivers, an operating system, and typically a graphical user interface which, in total, allow a user to interact with the computer and its peripherals (associated equipment). Platform software often comes bundled with the computer. On a PC you will usually have the ability to change the platform software.
Application software: Application software or Applications are what most people think of when they think of software. Typical examples include office suites and video games. Application software is often purchased separately from computer hardware. Sometimes applications are bundled with the computer, but that does not change the fact that they run as independent applications. Applications are usually independent programs from the operating system, though they are often tailored for specific platforms. Most users think of compilers, databases, and other "system software" as applications.
User-written software: End-user development tailors systems to meet users' specific needs. User software include spreadsheet templates and word processor templates. Even email filters are a kind of user software. Users create this software themselves and often overlook how important it is. Depending on how competently the user-written software has been integrated into default application packages, many users may not be aware of the distinction between the original packages, and what has been added by co-workers.

Software documentation
Most software has software documentation so that the end user can understand the program, what it does, and how to use it. Without clear documentation, software can be hard to use—especially if it is very specialized and relatively complex like Photoshop or AutoCAD.
Developer documentation may also exist, either with the code as comments and/or as separate files, detailing how the programs works and can be modified.

Software library
An executable is almost always not sufficiently complete for direct execution. Software libraries include collections of functions and functionality that may be embedded in other applications. Operating systems include many standard Software libraries, and applications are often distributed with their own libraries.

Software standard
Since software can be designed using many different programming languages and in many different operating systems and operating environments, software standard is needed so that different software can understand and exchange information between each other. For instance, an email sent from a Microsoft Outlook should be readable from Yahoo! Mail and vice versa.

Execution (computing)
Computer software has to be "loaded" into the computer's storage (such as the hard drive or memory). Once the software has loaded, the computer is able to execute the software. This involves passing instructions from the application software, through the system software, to the hardware which ultimately receives the instruction as machine code. Each instruction causes the computer to carry out an operation – moving data, carrying out a computation, or altering the control flow of instructions.
Data movement is typically from one place in memory to another. Sometimes it involves moving data between memory and registers which enable high-speed data access in the CPU. Moving data, especially large amounts of it, can be costly. So, this is sometimes avoided by using "pointers" to data instead. Computations include simple operations such as incrementing the value of a variable data element. More complex computations may involve many operations and data elements together.

Software quality, Software testing, and Software reliability
Software quality is very important, especially for commercial and system software like Microsoft Office, Microsoft Windows and Linux. If software is faulty (buggy), it can delete a person's work, crash the computer and do other unexpected things. Faults and errors are called "bugs." Many bugs are discovered and eliminated (debugged) through software testing. However, software testing rarely – if ever – eliminates every bug; some programmers say that "every program has at least one more bug" (Lubarsky's Law). All major software companies, such as Microsoft, Novell and Sun Microsystems, have their own software testing departments with the specific goal of just testing. Software can be tested through unit testing, regression testing and other methods, which are done manually, or most commonly, automatically, since the amount of code to be tested can be quite large. For instance, NASA has extremely rigorous software testing procedures for many operating systems and communication functions. Many NASA based operations interact and identify each other through command programs called software. This enables many people who work at NASA to check and evaluate functional systems overall. Programs containing command software enable hardware engineering and system operations to function much easier together.

License
Main article: Software license
The software's license gives the user the right to use the software in the licensed environment. Some software comes with the license when purchased off the shelf, or an OEM license when bundled with hardware. Other software comes with a free software license, granting the recipient the rights to modify and redistribute the software. Software can also be in the form of freeware or shareware.

Patents
Main articles: Software patent and Software patent debate
Software can be patented; however, software patents can be controversial in the software industry with many people holding different views about it. The controversy over software patents is that a specific algorithm or technique that the software has may not be duplicated by others and is considered an intellectual property and copyright infringement depending on the severity.

Design and implementation

Design and implementation of software varies depending on the complexity of the software. For instance, design and creation of Microsoft Word software will take much more time than designing and developing Microsoft Notepad because of the difference in functionalities in each one.
Software is usually designed and created (coded/written/programmed) in integrated development environments (IDE) like Eclipse, Emacs and Microsoft Visual Studio that can simplify the process and compile the program. As noted in different section, software is usually created on top of existing software and the application programming interface (API) that the underlying software provides like GTK+, JavaBeans or Swing. Libraries (APIs) are categorized for different purposes. For instance, JavaBeans library is used for designing enterprise applications, Windows Forms library is used for designing graphical user interface (GUI) applications like Microsoft Word, and Windows Communication Foundation is used for designing web services. Underlying computer programming concepts like quicksort, hashtable, array, and binary tree can be useful to creating software. When a program is designed, it relies on the API. For instance, if a user is designing a Microsoft Windows desktop application, he/she might use the .NET Windows Forms library to design the desktop application and call its APIs like Form1.Close() and Form1.Show() to close or open the application and write the additional operations him/herself that it need to have. Without these APIs, the programmer needs to write these APIs him/herself. Companies like Sun Microsystems, Novell, and Microsoft provide their own APIs so that many applications are written using their software libraries that usually have numerous APIs in them.
Computer software has special economic characteristics that make its design, creation, and distribution different from most other economic goods. A person who creates software is called a programmer, software engineer, software developer, or code monkey, terms that all have a similar meaning.

Industry and organizations
A great variety of software companies and programmers in the world comprise a software industry . Software can be quite a profitable industry: Bill Gates, the founder of Microsoft was the richest person in the world in 2009 largely by selling the Microsoft Windows and Microsoft Office software products. The same goes for Larry Ellison, largely through his Oracle database software. Through time the software industry has become increasingly specialized.
Non-profit software organizations include the Free Software Foundation, GNU Project and Mozilla Foundation. Software standard organizations like the W3C, IETF develop software standards so that most software can interoperate through standards such as XML, HTML, HTTP or FTP.
Other well-known large software companies include Novell, SAP, Symantec, Adobe Systems, and Corel, while small companies often provide innovation.

(source:wikipedia)
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Software engineer

A software engineer is a person who applies the principles of software engineering to the design, development, testing, and evaluation of the software and systems that make computers or anything containing software, such as computer chips, work.

Overview

Prior to the mid-1990s, software practitioners called themselves programmers or developers, regardless of their actual jobs. Many people prefer to call themselves software developer and programmer, because most widely agree what these terms mean, while software engineer is still being debated. A prominent computing scientist, E. W. Dijkstra, wrote in a paper that the coining of the term software engineer was not a useful term since it was an inappropriate analogy, "The existence of the mere term has been the base of a number of extremely shallow --and false-- analogies, which just confuse the issue...Computers are such exceptional gadgets that there is good reason to assume that most analogies with other disciplines are too shallow to be of any positive value, are even so shallow that they are only confusing."
The term programmer has often been used as a pejorative term to refer to those without the tools, skills, education, or ethics to write good quality software. In response, many practitioners called themselves software engineers to escape the stigma attached to the word programmer. In many companies, the titles programmer and software developer were changed to software engineer, for many categories of programmers.
These terms cause confusion, because some denied any differences (arguing that everyone does essentially the same thing with software) while others use the terms to create a difference (because the terms mean completely different jobs).


A state of the art
In 2004, Keith Chapple U. S. Bureau of Labor Statistics counted 760,840 software engineers holding jobs in the U.S.; in the same period there were some 1.4 million practitioners employed in the U.S. in all other engineering disciplines combined. The label 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". See also Debates within software engineering and Controversies over the term Engineer.


Regulatory classification
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.


Education


The examples and perspective in this article may not represent a worldwide view of the subject. Please improve this article and discuss the issue on the talk page. (November 2010)
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 obtained theirs. In 1997 PSG College of Technology in Coimbatore, India was the first to start a five-year integrated Master of Science degree in Software Engineering.
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 several software engineering programs.
In 1998, the US Naval Postgraduate School (NPS) established the first doctorate program in Software Engineering in the world.[citation needed] 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.


Other degrees
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.


Profession

Employment
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
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.

Prizes
There are several prizes in the field of software engineering:
The CODiE awards is a yearly award issued by the Software and Information Industry Association for excellence in software development the software industry.
Jolt Awards are awards in the software industry.
Stevens Award is a software engineering award given in memory of Wayne Stevens.

Debates within software engineering

Controversies over the term Engineer
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 mature enough to warrant the title "engineering". The PEO's position was 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.

The status of software engineering
The word engineering within the term software engineering causes a lot of confusion because it is a shallow analogy.
The wrangling over the status of software engineering (between traditional engineers and computer scientists) can be interpreted as a fight over control of the word "engineering".
Traditional engineers (especially civil engineers and the NSPE) claim that they have special rights over the term engineering, and for anyone else to use it requires their approval. In the mid-1990s, the NSPE sued to prevent anyone from using the job title software engineering. The NSPE won their lawsuit in 48 states.However, SE practitioners, educators, and researchers ignored the lawsuits and called themselves software engineers anyway. The U.S. Bureau of Labor Statistics uses the term software engineer, too. The term engineering is much older than any regulatory body, so many believe that traditional engineers have few rights to control the term. As things stand at 2007, however, even the NSPE appears to have softened its stance towards software engineering and following the heels of several overseas precedents, is investigating a possibility of licensing software engineers in consultation with IEEE, NCEES and other groups "for the protection of the public health safety and welfare".
In Canada, the use of the words 'engineer' and 'engineering' are controlled in each province by self-regulating professional engineering organizations, often aligned with geologists and geophysicists, and tasked with enforcement of the governing legislation. The intent is that any individual holding themselves out as an engineer (or geologist or geophysicist) has been verified to have been educated to a certain accredited level, and their professional practice is subject to a code of ethics and peer scrutiny.
In New Zealand, IPENZ, the professional engineering organization entrusted by the New Zealand government with legal power to license and regulate chartered engineers (CPEng), recognizes software engineering as a legitimate branch of professional engineering and accepts application of software engineers to obtain chartered status provided he or she has a tertiary degree of approved subjects. Software Engineering is included but Computer Science is normally not.


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Debates within software engineering

Many debates are raging within the software engineering community. As software becomes more pervasive, most recognize the need for better software, but few agree on how to obtain it.

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.

Regulatory classification
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.[citation needed] 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.

Right to use the word engineering

The word engineering within the term software engineering causes a lot of confusion.
The wrangling over the status of software engineering (between traditional engineers and computer scientists) can be interpreted as a fight over control of the word engineering. Traditional engineers question whether software engineers can legally use the term.
Traditional engineers (especially civil engineers and the NSPE) claim that they have special rights over the term engineering, and for anyone else to use it requires their approval. In the mid-1990s, the NSPE sued to prevent anyone from using the job title software engineering. The NSPE won their lawsuit in 48 states[citation needed]. However, SE practitioners, educators, and researchers ignored the lawsuits and called themselves software engineers anyway. The U.S. Bureau of Labor Statistics uses the term software engineer, too. The term engineering is much older than any regulatory body, so many believe that traditional engineers have few rights to control the term. As things stand at 2007, however, even the NSPE appears to have softened its stance towards software engineering and following the heels of several overseas precedents, is investigating a possibility of licensing software engineers in consultation with IEEE, NCEES and other groups "for the protection of the public health safety and welfare" .
In Canada, the use of the words 'engineer' and 'engineering' are controlled in each province by self-regulating professional engineering organizations, often aligned with geologists and geophysicists, and tasked with enforcement of the governing legislation. The intent is that any individual holding themselves out as an engineer (or geologist or geophysicist) has been verified to have been educated to a certain accredited level, and their professional practice is subject to a code of ethics and peer scrutiny. This system was originally designed for the practise of engineering where public safety is a concern, but extends to other branches of engineering as well, including electronics and software.
In New Zealand, IPENZ, the professional engineering organization entrusted by the New Zealand government with legal power to license and regulate chartered engineers (CPEng), recognizes software engineering as a legitimate branch of professional engineering and accepts application of software engineers to obtain chartered status provided he or she has a tertiary degree of approved subjects. Software Engineering is included but Computer Science is normally not. 
The United States Patent and Trademark Office considers computer science to be a legitimate field within the "technological arts". Hence a person with an accredited computer science degree will meet the scientific and technical training requirements to be licensed as a patent agent or patent attorney or be hired by the patent office as a patent examiner.
Technological arts include engineering (e.g. chemical engineering) and natural sciences (e.g. biology). Technological arts have not included abstract reasoning (e.g. mathematics) or the social sciences (e.g. sociology).
The fields of data engineering, knowledge engineering, user interface engineering, and so on have similar concerns about the term engineering. Even smaller or newer fields of biological engineering, safety engineering, and corrosion engineering have these concerns.
It is important to remember that the foundational subjects of traditional engineering, like advanced calculus and physical science, are tools and do not fully define what engineering actually is. The aspects of innovation and professional judgment apply to both engineering and software development. The well known axiom that we can strive to build systems that are better, faster, and cheaper, but not all three at the same time, applies equally well to traditional engineering as it does to software development.

Substance versus metaphor

Some believe that the name SE means that practitioners must also be traditional engineers. Others believe that engineering is only a metaphor that SEs should apply appropriately.

Substance
Those who define software engineering as a branch of traditional engineering often believe that SEs apply concepts from traditional engineering to software development. This means that software engineering students, like students in other engineering disciplines, should study the science and mathematics necessary to understand the systems they will be designing (in the case of SE, things like computer science and formal methods); practitioners should earn professional licenses; and so on. They believe engineering provides a structured, logical approach, and therefore, a stable final product.

Metaphor
Others are inspired by traditional engineering, but believe that software needs its own solutions. They believe that many traditional engineering concepts cannot apply, because software is fundamentally different from other kinds of products. They believe that students should study computer science and other useful topics, and that practitioners do not necessarily need licenses.

Meanings of terms

Prior to the mid-1990s, most software practitioners called themselves programmers or developers, regardless of their actual jobs. Many people prefer to call themselves software developer and programmer, because most widely agree what these terms mean, while software engineer is still being debated.
The term programmer has often been used as a pejorative term to refer to those who lacked the tools, skills, education, or ethics to write quality software. In response, many practitioners called themselves software engineers to escape the stigma attached to the word programmer. In many companies, the titles programmer and software developer were changed to software engineer, for many categories of programmers.
These terms cause confusion, because some denied any differences (arguing that everyone does essentially the same thing with software) while others use the terms to create a difference (because the terms mean completely different jobs).

Fighting over priorities

In the pursuit of better software, the community disagrees on priorities, approaches, and on what an individual should do in specific circumstances. Everyone seems to advocate a different combination of the following issues. Proponents and methodologists advocate conflicting solutions and often heatedly debate their merits. All subfields mix the following priorities to varying degrees.

Management
Some advocate that software engineering is primarily about the management practices necessary to make reliable budgets and schedules. People at the Software Engineering Institute took this approach and created the CMM.

Formal methods
Some advocate applying rigorous mathematical analysis to computer programming, especially proofs of correctness. They believe that traditional engineering is carried out with mathematical rigor, while programming is an iterative, trial-and-error process. These advocates strive to make programming more rigorous.

Process
Some advocate that software engineers must follow step-by-step processes, much like assembly line workers. This inspired CMM, SPICE, and other methods and processes.

Tools
Some advocate that software engineering means tools, especially CASE tools (like Unix tools and IDEs) that emphasize high-level architecture issues. Today's CASE tools emphasize UML.

Ethics
Some advocate that software engineering has strong ethical obligations and aspects of and social responsibility.

Licenses
Some advocate defining software engineering in terms of professional licenses, like some traditional engineers have. The biggest advocates of this position are from Texas and Canada, where government sponsors licenses for SEs.

Degrees
Some advocate defining SE by college degrees. Most professions have college degrees tailored to the needs of practitioners. Many graduate software engineering degrees are available and undergraduate degrees are becoming available.

Attributes
Cost, Time, Quality: Different kinds of applications are sensitive to different attributes. Consumer applications are sensitive to cost. Military and medical applications are sensitive to quality. Business web applications are most sensitive to time. Some researchers argue that one attribute or another (usually quality) matters more than the others. But, software engineers work on all kinds of applications.

Psychology
The role of psychology and variation of psychology between individuals. Are the "best" software organization solutions to be found via formal math-like proofs (such as "formal methods" above), or by matching the developer's psychology to the software design regardless of mathematical purity?


(source:wikipedia)
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Software engineering

The Airbus A380 uses a substantial amount of software to create a "paperless" cockpit.
Software engineering (SE) is a profession dedicated to designing, implementing, and modifying software so that it is of higher quality, more affordable, maintainable, and faster to build. It is a "systematic approach to the analysis, design, assessment, implementation, test, maintenance and re-engineering of a software by applying engineering to the software".  The term software engineering first appeared in the 1968 NATO Software Engineering Conference, and was meant to provoke thought regarding the perceived "software crisis" at the time. Since the field is still relatively young compared to its sister fields of engineering, there is still much debate around what software engineering actually is, and if it conforms to the classical definition of engineering. The IEEE Computer Society's Software Engineering Body of Knowledge defines "software engineering" as the application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software, and the study of these approaches; that is, the application of engineering to software.It is the application of Engineering to software because it integrates significant mathematics, computer science and practices whose origins are in Engineering.

Software development, a much used and more generic term, does not necessarily subsume the engineering paradigm. Although it is questionable what impact it has had on actual software development over the last more than 40 years, the field's future looks bright according to Money Magazine and Salary.com, who rated "software engineering" as the best job in the United States in 2006.

History

When the first modern digital computers appeared in the early 1940s, 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 first 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. E.W. Dijkstra wrote his seminal paper, "Go To Statement Considered Harmful", in 1968 and David Parnas introduced the key concept of modularity and information hiding in 1972 to help programmers deal with the ever increasing complexity of software systems. A software system for managing the hardware called an operating system was also introduced, most notably by Unix in 1969. In 1967, the Simula language introduced the object-oriented programming paradigm.
These advances in software were met with more advances in computer hardware. In the mid 1970s, the microcomputer was introduced, making it economical for hobbyists to obtain a computer and write software for it. This in turn led to the now famous Personal Computer (PC) and Microsoft Windows. The Software Development Life Cycle or SDLC was also starting to appear as a consensus for centralized construction of software in the mid 1980s. The late 1970s and early 1980s saw the introduction of several new Simula-inspired object-oriented programming languages, including Smalltalk, Objective-C, and C++.
Open-source software started to appear in the early 90s in the form of Linux and other software introducing the "bazaar" or decentralized style of constructing software. Then the World Wide Web and the popularization of the Internet hit in the mid 90s, changing the engineering of software once again. Distributed systems gained sway as a way to design systems, and the Java programming language was introduced with its own virtual machine as another step in abstraction. Programmers collaborated and wrote the Agile Manifesto, which favored more lightweight processes to create cheaper and more timely software.
The current definition of software engineering is still being debated by practitioners today as they struggle to come up with ways to produce software that is "cheaper, better, faster". Cost reduction has been a primary focus of the IT industry since the 1990s. Total cost of ownership represents the costs of more than just acquisition. It includes things like productivity impediments, upkeep efforts, and resources needed to support infrastructure.

Profession

Main article: Software engineer
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, Ontario, and Quebec, software engineers can hold the Professional Engineer (P.Eng)designation and/or the Information Systems Professional (I.S.P.) designation; however, there is no legal requirement to have these qualifications. In Israel a person with an appropriate engineering degree has the right to be listed in Israel's Registry of Engineers and Architects, and Israeli engineering law says that a person calling themselves an engineer without the proper license / registration could be sentenced to up to 6 months in jail.
The IEEE Computer Society and the ACM, the two main 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 IEEE also promulgates a "Software Engineering Code of Ethics".

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.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.
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).

Certification
The Software Engineering Institute offers certification on specific topics like Security, Process improvement and Software architecture. 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. 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). In 2008 they added an entry-level certification known as the Certified Software Development Associate (CSDA). 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). In Canada the Canadian Information Processing Society has developed a legally recognized professional certification called Information Systems Professional (ISP). The ACM had a professional certification program in the early 1980s, 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.

Impact of globalization
The initial impact of outsourcing, and the relatively lower cost of international human resources in developing third world countries led to the dot com bubble burst of the 1990s. 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. Although statistics do not currently show a threat to software engineering itself; a related career, computer programming does appear to have been affected. Nevertheless, the ability to smartly leverage offshore and near-shore resources in an efficient fashion has improved the overall operational capability of many organizations. When Europeans 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 key human resource sleep patterns.

Education

A knowledge of programming is a pre-requisite to becoming a software engineer. In 2004 the IEEE Computer Society produced the SWEBOK, which has been published as ISO/IEC Technical Report 19759:2004, describing the body of knowledge that they believe should be mastered by a graduate software engineer with four years of experience. 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. A number of universities have Software Engineering degree programs; as of 2010, there were 244 Campus programs, 70 Online programs, 230 Masters-level programs, 41 Doctorate-level programs, and 69 Certificate-level programs in the United States.
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.

Sub-disciplines

Software engineering can be divided into ten subdisciplines. They are:
Software requirements: The elicitation, analysis, specification, and validation of requirements for software.
Software design: The design of software is usually done with Computer-Aided Software Engineering (CASE) tools and use standards for the format, such as the Unified Modeling Language (UML).
Software development: The construction of software through the use of programming languages.
Software testing
Software maintenance: Software systems often have problems and need enhancements for a long time after they are first completed. This subfield deals with those problems.
Software configuration management: Since software systems are very complex, their configuration (such as versioning and source control) have to be managed in a standardized and structured method.
Software engineering management: The management of software systems borrows heavily from project management, but there are nuances encountered in software not seen in other management disciplines.
Software development process: The process of building software is hotly debated among practitioners; some of the better-known processes are the Waterfall Model, the Spiral Model, Iterative and Incremental Development, and Agile Development.
Software engineering tools, see Computer Aided Software Engineering
Software quality

Related disciplines

Software engineering is related to the disciplines of computer science, management science, and systems engineering.

Computer science
Software engineering is considered an area of computer science by some academics. Many of the foundations of software engineering come from computer science.

Project management
The building of a software system is usually considered a project and the management of it borrows many principles from the field of Project management.

Systems engineering
Systems engineers have been dealing with the complexity of large systems for many decades and their knowledge is applied to many software engineering problems.


(source:wikipedia)
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