This work describes a case study which demonstrates the efficacy of a renew
al process of a very old system, judged from the viewpoint of users and man
agers. Data were collected over three years in a real environment to assess
the effectiveness of the process, performed on a banking software system.
The effects attributable to the progressive ageing of a system perceived by
its users and managers were first individuated. After the process, such su
ccesses as a drop in the costs of maintenance and an increase in transferab
ility and testability of the programs were recorded. There were also some f
ailures, notably insufficient improvement in the quality of the programs an
d in their capacity to be modified. Finally, some conclusions are drawn as
to the opportunity of subdividing the renewal process into two macrophases,
reverse engineering and restoration, which integrate the process activitie
s generating the benefits. Although these are conceptually distinguishable,
they must be executed together to obtain the desired benefits from the ren
ewal process. (C) 1999 Published by Elsevier Science Inc. All rights reserv
ed.