In this paper we present a case study of the software maintenance practice
that has been successfully applied to real-time distributed systems, which
are installed and fully operational in Moscow, St. Petersburg, and other ci
ties across Russia. In this paper we concentrate on the software maintenanc
e process, including customer request servicing, in-field error logging, ro
le of information system, software deployment, and software quality policy,
and especially the software quality prediction process. In this case study
, the prediction process Is shown to be integral and one of the most import
ant parts of the software maintenance process. We include a software qualit
y prediction procedure overview and an example of the actual practice. The
quality of the new software update is predicted on the basis of the current
update's quantity metrics data and quality data, and new update's quantity
metrics data. For management, this forecast aids software maintenance effi
ciency, and cost reduction. For practitioners, the most useful result prese
nted is the process for determining the value for the break point. We end t
his case study with five lessons learned. Copyright (C) 2001 John Wiley & S
ons, Ltd.