|ISO.3 Conformity between V-Model and ISO 12207|
The international standard ISO 12207 is a globally accepted standard for software lifecycle processes. Though not suited for the direct application in a concrete project, it offers a frame that national standards or corresponding process details to be integrated in order to achieve a standard that can be used in an actual case. Furthermore, the ISO 12207 standard includes definitions that can be applied as a basis for a common terminology, even in national standards.
The following includes an overview of the ISO 12207, and it is illustrated how the processes of the ISO 12207 are realized by the V-Model.
The ISO 12207 standard can be applied to the acquisition, the supply, the operation and the maintenance of systems/software, independent of the fact if the development took place internally or if it was placed with an external organization. This holds true for software as an independent product and as part of a complete system.
A typical application depends on the relationship between customer and contractor, whereby these roles may be allocated within one corporation as well. Apart from the software development, the standard also regulates the operation and maintenance of the system. It also takes into consideration aspects like quality assurance and project management.
To be used in a concrete project, the standard must be adjusted to the individual requirements (tailoring) whereby tasks without relevance will be eliminated.
The ISO 12207 standard does not require a development model (LC model) but delivers a software lifecycle into which, in the case of a concrete project, a specially selected development model/V-Model has to be integrated or to be mapped. By using processes that will be structured into activities, the ISO 12207 describes the software lifecycle. The activities are again decomposed into tasks which, however, since no actual V-Model is to be specified, will not be realized, neither as a whole nor in detail. The ISO 12207 standard does not contain any regulations about methods to be applied or about products to be generated, either. This decision is left to the user of the standards.
Figure ISO.3 shows an overview of the processes regulated in the ISO 12207 standard: five "primary" processes (acquisition, supply, development, operation, maintenance), eight "supporting" processes (documentation, configuration management, quality assurance, verification, validation, joint review, audit, problem resolution), and four "organizational" processes (management, infrastructure, improvement, training).
The organizational processes are controlled by all primary processes, the primary processes initiate also the supporting processes, and in part they also activate each other.
The ISO 12207 standard structures the software lifecycle on the basis of five different roles (also called "major parties"). These major parties are integrated into the lifecycle of the software, depending on each individual current process being realized. These roles either control a process themselves, or they are responsible for the realization and initiate and control the process.
Acquirer: This role is in charge of the acquisition process, from the definition of requirements and the initiation to the control of the contractor up to the acceptance.
Supplier: This role is in charge of the supply process, it begins with the placement of the order and the signing of the contract and ends with the delivery.
Developer: This role is in charge of the actual development process; it may even include the system requirement analysis, and it ends with the installation and introduction of the system.
Operator: This role is in charge of the operation process and comprises review, realization, and support of the operation.
Maintainer: This role is in charge of the maintenance process; it begins with modification and ends with migration and finally software "retirement".
|This page online GDPA Online Last Updated 03.Mar.2004 by C. Freericks|