Maintenance - proposed definition for software engineering Use of the terms care and maintenance is carried out in software engineering is not always in a consistent manner. This is probably due to the fact that the dominant English language in general use both terms in "Maintenance" sums up.
Under maintenance in the strict sense in the software technique to locate and correct understanding of residual errors, ie the removal of such errors, which were before the introduction of the software product not found more and / or no longer fixed. Thus, the maintenance is to be regarded as a "remaining work" of development (see Balzert, H.: Handbook of Software Technology, Volume I, 1996, Spektrum-Verlag, p. 967). Since during the maintenance errors can arise, are the elimination of these "second-level defects" and other measures to stabilize the technical part of the software product maintenance.
In general, the software is delivered, without that all possible and reasonable Measures have been implemented to improve performance. It is usually limited to the absolutely necessary measures to take on the software product as quickly as possible in production. This means that the maintenance by extension, develop the technical optimization of the system includes.
Both aspects collectively, the term software maintenance, defined in Wikipedia as: "In software engineering, the term maintenance and services to maintain the availability and reliability of software. Maintenance of software is making a significant contribution to the security of investment "(Wikipedia.org, accessed on: 13/09/2005, Online at:
http://de.wikipedia.org/wiki/Softwarewartung ).
This definition implies that there is a state which is guaranteed in the availability and reliability of the software and the related investment. This state of things will usually neglected in definitions of software engineering, but it forms the core in the lt for industrial DIN 31051 provided for the definition of maintenance: "measures to maintain the desired state of technical means of a system (DIN 31051, Part 1 / 12.74). It seems important that it starts at the set state of the DIN, a once defined, as set out Target state is.
Due to changes in the environment of the system (eg through new system software) can set a new state, relative to default result defined desired state. To identify action resulting from it, it is necessary to determine the discrepancies. serves this purpose (according to) the inspection, during which the actual state of a system is identified and assessed.
The concept of repair is signified by the DIN "measures to restore the desired state of a system of technical means" (ibid.).
the concept of repair DIN should have in mind when one of software engineering in the established concept of "care" more detailed consideration. Balzert include the adjustment and modification of the software system to changing environmental conditions, and the extension (ie, functional addition for professional or technical reasons) as functions of care (see Balzert, H.: Handbook of Software Technology, Volume I, 1996, Spektrum-Verlag, p. 967f. and p. 969). At the same time he warns against running in the care and maintenance phase of a software system's development. What is of (such as in evolutionary process models) for the next version of the product, another pass through the software life cycle rather reasonable and the maintenance phase should focus on minimal changes.
Assuming a maintenance phase, which focuses on small changes, one could describe the adjustment and modification of the software system to changing environmental conditions than care. The expansion and additional counts will no longer care. Thus, the concept of care to the concept of repair as per DIN would correspond, so that you can define: Software maintenance includes all actions to restore the desired state of a software system due to changing environmental conditions.
In connection with software maintenance are introduced by the ISO 12207 different types of software maintenance:
- corrective maintenance - for the elimination of errors
- Adaptive maintenance - adapting the software to changing conditions and technical
- peferktionierende maintenance - to complete and the Improvement of functions.
In addition, sometimes even in the prevention of distinguished fault preventive maintenance (to Wikipedia.org, visited on: 13.09.2005, online at:
http://de.wikipedia.org/wiki/Softwarewartung ).
Corrective maintenance would correspond to the maintenance concept, as he was already defined above. Adaptive maintenance corresponds to the concept of care, which was defined here in accordance with the repair. The development of the system is to be regarded as perfect their maintenance. Without reference is preventive, preventive maintenance error.
summary, add a definition for the term here, given the care and maintenance of established standards of ISO and DIN and not collide with the previously soft terminology of software engineering. Therefore the following definition proposed for the terms "maintenance" is (syn. "Software Maintenance") and "care" (syn. "Software Maintenance") provided:
Maintenance: All measures to maintain the defined desired state of a software system by troubleshooting, technical stabilization and performance improvement to maintain the availability, reliability and investment protection.
Maintenance: All measures for the restoration of the defined desired state of a software system due to changing environmental conditions by slight adjustment of already implemented functions to maintain the availability, reliability and investment protection. introduce
