Abstract
Open source software has become a significant factor to industrial software development with regard to economic efficiency and the development life cycle. Software vendor companies participates in the open source communities by using existing open source software as well as providing professional programmers to the open source communities as their jobs. This article introduces two case developments that we ran contracted developments in parallel to open source libraries for economical efficiency of the contracted developments and also concrete applications of the open source libraries. Expectations to OSS engineering will also be presented.
