Information Technology Reference
In-Depth Information
11.4 Development and Maintenance
Once the product has passed its acceptance test, it is handed over to the client. The
product is installed and used for the purpose of which it was constructed. However,
it will almost certainly need to undergo post-delivery maintenance, either to fix
faults or extend the functionality of the product. Because a product consists of
more than just the source code, any changes to the documentation, manual or any
other component of the product after it has been delivered to the client are
examples of post-delivery maintenance (Schach
2007
).
11.5 Why Post-Delivery Maintenance is Necessary
There are three main reasons for making changes to a product (Schach
2007
):
• A fault needs correcting, whether an analysis fault, design fault, coding fault,
documentation fault, or any other type of fault. This is termed corrective
maintenance.
• In perfective maintenance, a change is made to the code in order to improve the
effectiveness of the product. For instance, the client may wish for additional
functionality or request that the product be modified so that it runs faster.
• In adaptive maintenance, a change to the product is made in order to react to a
change in the environment in which the product operates.
11.6 What is Required of Post-Delivery Maintenance
Programmers?
During the software life cycle, more time is spent on post-delivery maintenance
than on any other activity. In fact, on average, at least 67 % of total cost can be
attributed to post-delivery maintenance (Schach
2007
). Post-Delivery maintenance
is the most difficult of all aspects of software production, a major reason is that
post-delivery maintenance incorporates aspects of all the other work-flows of the
software process. A defect report is filed if, in the opinion of the user, the product
is not working as specified in the user manual. One of the first possible causes
could be that the user has misunderstood the user manual or is simply using the
product incorrectly. Sometimes the user manual might be poorly worded and
nothing could be wrong in the code. Another possible cause is that there is actually
a fault in the code. Before making any changes, it is vital that the maintenance
programmer needs to have above average debugging skills. Suppose that the
maintenance programmer has located a fault and must fix it without inadvertently
