The Transistor
Today in 1902 is the birthday of physicist Walter Houser Brattain, co-inventor of the transistor. The transistor is the basic circuit of all digital computers. The invention of the first transistor garnererd Brattain, William Shockley and John Bardeed the 1956 nobel prize.
In fact, an estimate of computer chip's performance can be given by the number of transistors in it. Transistor count is related to Moore's law, which says that the number of tranistors in the fastest microchips doubles every 24 months.
The first IBM PC had about 29,000 transistors in its CPU. Modern computer CPUs contain hundreds of millions of transistors.
 Deep Blue
Also today in 1996 was the day that "Deep Blue", a computer, beat the World chess champion for the first time. Gary Kasparov, arguably the best chess player of all time was beaten by a computer that consisted of approximately 480 million transistors. Deep blue was capable of calculating approximately 200,000,000 chess positions per second. Even with all that horsepower, the computer couldnâ't win every game against the champ.
Today, a typical microprocessor used in a PC, such as an Intel Core duo, has about 290 million transistors, although the PC's circuitry isn't optimized for chess.
Project Deep Blitz is a recent attempt to make a computer using off the shelf components that would be more competive than Deep Blue. There's an interesing table in the link that shows the relationship between chess rating and calculated moves-per-second.
(c) 2007, Jorge Monasterio