This paper presents author experience with software development during last forty years. It is divided into three eras: closed and open -systems and Internet of Everything, each covered by challenges, issues and solutions. The main stream is given from the interoperability perspective and flavored by security issues. Variety of applications domains, that author faced during his carrier, each with own challenges, is presented. Example include computer graphics systems, special-purpose solutions, business-to-business, business process management, e-government, and smart cities.