This machine has some remarkable properties. It does addition or subtraction at the rate of 3500 per second. It does multiplication or division at the rate of 1000 per second. The input is from a keyboard or magnetic tape; the output is to magnetic tape or an electric typewriter. Binac has 512 registers of very rapid memory in mercury tanks, and each register holds 30 binary digits. The machine actually is a pair of twins: the storage, the computing element, and the control are double, and each twin runs in step with the other and checks every operation of the other. In tests in July the machine ran over 10 consecutive hours with no error. Each twin has only 700 electronic tubes. Binac handles all numbers in binary notation, except that the keyboard and the typewriter express numbers in _octal notation_ (see Supplement 2). Finally, Binac is only 5 feet high, 4 feet long, and one foot wide. Chapter 11 THE FUTURE: MACHINES THAT THINK, AND WHAT THEY MIGHT DO FOR MEN The pen is mightier than the sword, it is often said. And if this is true, then the pen with a motor may be mightier than the sword with a motor. In the Middle Ages, there were few kinds of weapons, and it was easy for a man to protect himself against most of them by wearing armor. As gunpowder came into use, a man could no longer carry the weight of armor that would protect him, and so armor was given up. But in 1917, armor, equipped with a motor and carrying the man and his weapons, came back into service—as the tank. In much the same way, in the Middle Ages, there were few books, and it was easy for a man to handle nearly all the information that was in books. As the printing press came into use, man’s brain could no longer handle all recorded information, and the effort to do so was given up. But in 1944, a brain to handle information, equipped with a motor and supporting the man and his reasoning, came into existence—as the sequence-controlled calculator. In previous chapters we have examined some of the giant mechanical brains that have been finished; we have also considered the design of such machines. Now in this chapter we shall discuss the future significance of machines that think, of motorized information. We shall discuss what we can foresee if we look with imagination into the future. There are two questions we need to ask: What types of machines that think can we foresee? What types of problems to be solved by these machines can we foresee? FUTURE TYPES OF MACHINES THAT THINK The machines that already exist show that some processes of thinking can already be performed very quickly: Calculating: adding, subtracting,... Reasoning: comparing, selecting,... Referring: looking up information in lists,... We can expect other processes of thinking to come up to high speed through the further development of thinking machines. Automatic Address Book