This paper presents and discusses the ReTINA approach to distributed object-based middleware. It is based on a minimal but highly flexible framework for the construction of Object Request Brokers (ORBs). The ReTINA ORB framework supports the introduction of arbitrary binding mechanisms, including arbitrary communication protocols and communication stacks, and fine-grained control of system-level resources. This makes up for a highly scalable ORB (“from mobile phone to mainframe”) which supports the development of applications with temporal quality of service constraints.