Lessons learned from the OS/400 OO project

Abstract

This article describes some of the lessons learned when a team of 150 developers with a minimal prior exposure to object-oriented (OO) technology undertook a large development project. Team members became proficient in OO design, using C++ as an OO language rather than just using C++ as a better C, and developed IBM's RISC version of the AS/400 and System/36 operating systems from 1992 to 1994 in Rochester, Minnesota. The project contains 14,000 thousand classes, 90,000 thousand methods, and 2 million lines of C++ integrated into 20 million lines of total code. The result of their efforts was the development of a product that is being used daily by a substantial international customer base.