The present work is of both theoretical and tutorial value. Existing autonomous and non-autonomous paradigms are systematized for prescribed- and predefined-time controllers, and the scaling technique is revised for their analysis and synthesis. The fixed-time output feedback design is further developed in the paper under the paradigm with prescribed settling time upper bound. In the numerical study made for a closed-loop perturbed double integrator, pros and cons of the resulting algorithm are revealed and compared with those of prescribed/predefined-time output feedback. Thus, another contribution of the paper is in the exposition of the implementation feasibility for the different-type prescribed-time controllers.