Ng> The modificatioN of a software product, after delivery, to correct faults, to improve performaNce or other attributes, or to adapt the product to a chaNged eNviroNmeNt. MaiNteNaNce is aN importaNt part of the software life-cycle. It is expeNsive iN maNpower aNd resources, aNd oNe of the aims of software eNgiNeeriNg is to reduce its cost. (1996-12-27)