Creating Software: Software Life Cycle

Software is the result of the software development process. The steps in the process are as follows:

systems analysis: determining the functionality of the application and creating a requirements specification. The requirement details the way the software should operate, the data it will use, and the functions it should perform. Generally conducted by systems analysts. If software is to be internationalized, the internationalization requirements should be specified here, with a specific section in the requirements specification.

software design: using the requirements specification to create a detailed outline or blueprint for the software. Software design includes designing the most appropriate data structures and outlining the specific sets of instructions (logic) of the required functions. The design specification that results from this stage is not (necessarily) written in a programming language, but may be written in a form of structured English called pseudocode. The design of the program is crucial to its smooth running, and there are various techniques and methods that allows a programmer to design how an application should be constructed.

programming: the design specification will be used to implement the design in a program (a set of executable instructions written in a specific programming language). A program is a set of of data structures and the algorithms for manipulating them. The program is implemented in a programming language.

programming language: a programming language provides a set of operators, reserved words, programming structures (IF-THEN-ELSE, CASE, SEQUENCE, DO LOOP) and built-in functions to allow programmers to implement a functional logic in the instruction set of several target chip instruction sets ( a platform). Older programming languages are so-called procedural programming languages (COBOL, FORTRAN, PASCAL) while almost newer programming languages used for writing programs today are object-oriented programming languages (Visual Basic, Visual C++ and C++, Smalltalk, etc.)

testing and verification: after programming the application program is debugged and its functional operation verified.

delivery: application program is delivered to the customer
maintenance: the system is modified to meet the changing needs of the user; episodic upgrades are offered as new functions are demanded or available.