上充￥1.4 Software Characteristics SHANGHAI JIAO TONG UNIVERSITY © Software is developed or engineered,it is not manufactured in the classical sense Software doesn't wear out Failure Rate Increased Failure failure rate due Wear out Rate to side effects Actual curve Infant mortality Idealized Change curve Time Time Although the industry is moving toward component- based assembly,most software continues to be custom built Software EngineeringSoftware Engineering 1.4 Software Characteristics Software is developed or engineered, it is not manufactured in the classical sense Software doesn’t wear out Although the industry is moving toward component- based assembly, most software continues to be custom built Time Failure Rate Infant mortality Wear out Time Failure Rate Actual curve Idealized Change curve Increased failure rate due to side effects