A software development process is a structure imposed on the development of a software product. Synonyms include software life cycle and software process. There are several models for such processes, each describing approaches to a variety of tasks or activities that take place during the process.
All methods undertake the seven steps listed to different degrees:
Often the first step in attempting to design a new piece of software, whether it is an addition to existing software, a new application, a new subsystem or a whole new system, is what is generally referred to as “Domain Analysis”. Assuming that the developers (including the analysts) are not sufficiently knowledgeable in the subject area of the new software, the first task is to investigate the so-called “domain” of the software. The more knowledgeable they are about the domain already, the less the work required. Another objective of this work is to make the analysts who will later try to elicit and gather the requirements from the area experts or professionals, speak with them in the domain’s own terminology and to better understand what is being said by these people. Otherwise they will not be taken seriously. So, this phase is an important prelude to extracting and gathering the requirements. The following quote captures the kind of situation an analyst who hasn’t done his homework well may face in speaking with a professional from the domain: “I know you believe you understood what you think I said, but I am not sure you realize what you heard is not what I meant.”
Software Elements Analysis
The most important task in creating a software product is extracting the requirements. Customers typically know what they want, but not what software should do, while incomplete, ambiguous or contradictory requirements are recognized by skilled and experienced software engineers. Frequently demonstrating live code may help reduce the risk that the requirements are incorrect.
Once the general requirements are gleaned from the client, an analysis of the scope of the development should be determined and clearly stated. This is often called a scope document. Certain functionality may be out of scope of the development project as function of cost, others as a result of unclear requirements at the time the development has begun. If the development is done externally, this document can be considered a legal document so that if ever there are disputes, any ambiguity of what was promised to the client can be clarified.
Specification is the task of precisely describing the software to be written, possibly in a rigorous way. In practice, most successful specifications are written to understand and fine-tune applications that were already well-developed, although safety-critical software systems are often carefully specified prior to application development. Specifications are most important for external interfaces that must remain stable. A good way to determine whether the specifications are sufficiently precise is to have a third party review the documents making sure that the requirements are logically sound.
The architecture of a software system refers to an abstract representation of that system. Architecture is concerned with making sure the software system will meet the requirements of the product, as well as ensuring that future requirements can be addressed. The architecture step also addresses interfaces between the software system and other software products, as well as the underlying hardware or the host operating system.
Reducing a design to code may be the most obvious part of the software engineering job, but it is not necessarily the largest portion.
Testing of parts of software, especially where code by two different engineers must work together, falls to the software engineer.
After the code is appropriately tested and approved, it is moved into production environment i.e. is made available for business use.
An important (and often overlooked) task is documenting the internal design of software for the purpose of future maintenance and enhancement. Documentation is most important for external interfaces.
Computer World, 2002, Retrieved on June 22, 2006 from the World Wide Web: http://www.computerworld.com/developmenttopics/development/story/0,10801,71151,00.html
Software development life cycle (SDLC) [visual image], software development life cycle