Software engineering process in order to obtain high-quality software framework required to complete a series of tasks, which sets out the steps to complete the tasks of the job.
You must make some development activities in the completion of development tasks, and the use of appropriate resources (people, time, computer hardware, software, tools, etc.), at the end of the process input (such as software requirements) into outputs (such as software product), so , ISO9000 the process is defined as "input into a set of resources and activities related to each output."
Process defines the sequence using the method of documentation should be delivered, in order to ensure software quality management measures and coordination of changes need to be taken, as well as signs at all stages of software development tasks to complete the milestone. To obtain high-quality software products, the software engineering process must be scientific and rational.
Software-defined task is the overall goal of determining the period of software development projects must be completed; determine the feasibility of the project; strategies and systems engineering to achieve the export target should be used must complete function; estimated completion costs and resources required for the project, and the development of project schedule. The work of this period are often called systems analysis, systems analysts responsible for completion. Software-defined period is usually further divided into three stages, namely the problem definition, feasibility study and needs analysis.
Software development period specific design and implementation of the software defined previous period, which typically consists of the following four stages: the outline design, detailed design, coding and testing unit, integrated testing. The first two stages, also known as system design, the latter two phases, also known as system implementation.
The main task is to make the operation and maintenance period lasting software to meet the needs of users. Specifically, when the software error is found in the course it should be corrected; When the environment changes should modify the software to adapt to the new environment; when there are new user requirements should promptly improve the software to meet the new needs of users.
Usually not further divide the stage for the maintenance period, but each time maintenance on the definition and development activities are essentially a compressed and simplified.
The purpose of the feasibility study is to determine the problem with minimum cost in the shortest possible time is able to solve. We must remember that the purpose of the feasibility study is not the solution, but to determine whether the problem is worth solution. To achieve this purpose, we can not rely on subjective conjecture and can only rely on objective analysis. Further generalized systems analyst must understand the needs of users, and propose several possible system implementation on this basis, for each program are from such legal feasibility analysis and other technical, economic, and social factors, which ultimately determine the feasibility of projects.
Needs analysis task at this stage is still not specifically address customer problems, but accurately answer the question "What is the target system must do."
Although the feasibility study stage have a rough understanding of the needs of users, and even made a number of possible options, however, the basic purpose of the feasibility study is relatively small cost in a short period of time to determine whether there is a feasible solution with, So many details to be ignored. However, it can not miss any tiny details in the final system, it is not a substitute for a feasibility study and needs analysis, it actually does not accurately answer the question "what the system must do."
Needs analysis task is not to determine how the system do its work, but only to determine which systems work to be done, which is made complete, accurate, clear and specific requirements of the target system.
Users understand the problems they face, know what must be done, but usually can not completely and accurately express their demands, but do not know how to use computers to solve their problems; software developers know how to use the software requirements of the people, but specific requirements for a particular user is not entirely clear. Therefore, systems analysts must be closely coordinated with the user in the requirements analysis phase, the full exchange of information, in order to obtain user confirmation system requirements.
Another important task at this stage, is the official document accurately record demand for the target system, the document often referred to specification
