The first computers were like an actual wall refrigerator. They were composed of hundred of thermionic high vacuum valves. They were ostentatious. They spent a huge amount of electric energy. Only the big corporations, like the army of the United States, could be able to afford them. It was the year of 1952.
The situation changed. Shockley conjectured that the use of the transistor could change the shape of the computers. It happened so. And something else also occurred. For the transistor can be reduced is size, its possibilities are enormous. The transistors can be packed, by millions, in cubic millimitre. They interconnected right there. With them, the physicists built electronic memories, integrated circuits, tridimensional integrated circuits, etc. And with those dispositives, the physicists made clocks, televisions, etc. but mainly computers. The computers are the core of all automatized dispositives.
The attributes of the computers are the speed to process information and the capacity to store it. All the developments of the computations have been made in this direction. The first computer lacked of memory. It was the MANIAC I. And the year was 1952. It occupied the volume of a big desk. It did no see the market. The latest computers in the market have 1000 Mega Hertz in the clock speed, some million of units of RAM memory, and occupy the volume of regular folder three hundred page book. They operate, continuously for more than 4 hours, with a 12 Volts cigarette box size battery. They have infrared communication port, fax modem, port for diskettes and CD, stereophonic system sound, DVD player, and internal hard disk up to 50 GB.
With a high capacity of computation, other scientific areas were developed. Limited memory and limited speed are not big problems any more in these days. New technologies appear. New sciences. For example, the molecular biology, the molecular chemistry, the computational physics, etc. The very long calculations, that appear when the quantum mechanics is applied to a many body physical system, are not big problems any more. They can be made, now in these days, in a few hours in a medium size book computer.