This chapter talks about some technical possibilities for making machines. One is parallel processing machines which are something of the very near future, almost present, that is being developed now. Further in the future is the question of the energy consumption of machines which seems at the moment to be a limitation. An example of such a machine is the Connection Machine made at Massachusetts Institute of Technology. The chapter also talks about parallel computers. Almost all the present computers, conventional computers, work on a layout or an architecture invented by von Neumann, in which there is a very large memory that stores all the information, and one central location that does simple calculations. The chapter focuses on energy loss in computers. The fact that they must be cooled is an apparent limitation for the largest computers – a good deal of effort is spent in cooling the machine.