Thermal management of very large-scale computers will have to leave the traditional well-beaten path. Up to the present time, the primary concern has been with rising heat flux on the integrated circuit chip, while a space has been available for the implementation of high-performance cooling design. In future systems, the spatial constraint will become a primary determinant of thermal management methodology. To corroborate this perspective, the evolution of computer's hardware morphology is simulated. Simulation tool is the geometric model, where the model structure is composed of circuit cells and platforms for circuit blocks. The cell is the minimum circuit element whose size is pegged to the technology node, while the total number of cells represents the system size. The platforms are the models of microprocessor chips, multichip modules (MCMs), and printed wiring boards (PWBs). The major points of discussion are as follows: (1) The system morphology is dictated by the competition between the progress of technology node and the demand for increase in the system size. (2) Only where the miniaturization of cells is achieved so as to deploy a system on a few PWBs, ample space is created for thermal management. (3) In the future, the cell miniaturization will hit the physical limit, while the demand for larger systems will be unabated. Liquid cooling, where the coolant is driven through very long microchannels, may provide a viable thermal solution.