The Future of PCs

Silicon microprocessors have been the heart of the computing world for more than 40 years. In that time, microprocessor manufacturers have crammed more electronic devices onto microprocessors. In 1965, Intel founder Gordon Moore predicted that microprocessors would double in complexity every two years. Since then, the number of electronic devices put on a microprocessor has doubled every 18 months, and the prediction has come to be known as Moore's Law. Many have predicted that Moore's Law will soon reach its end because of the physical limitations of silicon microprocessors.

2008 HowStuffWorks
Extreme ultraviolet lithography is the future of computer-chip manufacturing.

­ T­he current process used to pack more transistors onto a chip is called deep-ultraviolet lithography (DUVL), which is a photography-like technique that focuses light through lenses to carve circuit patterns on silicon wafers. While new manufacturing techniques have extended the useful lifespan of the DUVL process, before long chip manufacturers will have to use new techniques to keep up with Moore's Law. Many are already looking at extreme-ultraviolet lithography (EUVL) as a way to extend the life of silicon at least until the end of the decade. EUVL uses mirrors instead of lenses to focus the light, which allows light with shorter wavelengths to focus on the silicon wafer accurately. To learn more about EUVL, see How EUVL Chipmaking Works.

Beyond EUVL, researchers have been looking at alternatives to the traditional microprocessor design. Two of the more interesting emerging technologies are DNA computers and quantum computers.

DNA computers have the potential to take computing to new levels, picking up where Moore's Law leaves off. There are several advantages to using DNA instead of silicon:

• As long as there are cellular organisms, there will be a supply of DNA.


• The large supply of DNA makes it a cheap resource.


• Unlike traditional microprocessors, which are made using toxic materials, DNA biochips can be made cleanly.


• DNA computers are many times smaller than today's computers.

DNA's key advantage is that it will make computers smaller than any computer that has come before, while at the same time increasing storage capacity. One pound (0.45 kilogram) of DNA has the capacity to store more information than all the electronic computers ever built. The computing power of a teardrop-sized DNA computer, using the DNA logic gates, will be more powerful than the world's most powerful supercomputer. More than 10 trillion DNA molecules can fit into an area no larger than 1 cubic centimeter (.06 cubic inch). With this small amount of DNA, a computer would be able to hold 10 terabytes (TB) of data and perform 10 trillion calculations at a time. By adding more DNA, more calculations could be performed.

Unlike conventional computers, DNA computers could perform calculations simultaneously. Conventional computers operate in linear fashion, taking on tasks one at a time. Parallel computing will allow DNA to solve complex mathematical problems in hours -- problems that might take electrical computers hundreds of years to complete. You can learn more about DNA computing in How DNA Computers Will Work.

Today's computers work by manipulating bits that exist in one of two states: 0 or 1. Quantum computers aren't limited to two states; they encode information as quantum bits, or qubits. A qubit can be a 1 or a 0, or it can exist in a superposition that is simultaneously 1 and 0 or somewhere in between. Qubits represent atoms that are working together to serve as computer memory and a microprocessor. Because a quantum computer can contain these multiple states simultaneously, it has the potential to be millions of times more powerful than today's most powerful supercomputers. A 30-qubit quantum computer would equal the processing power of a conventional computer capable of running at 10 teraops, or trillions of operations per second. To equal the top of the line in supercomputers you'd need more qubits. The Roadrunner supercomputer can run at a petaflop -- 1,000 trillian floating point operations per second. You can learn more about the potential of quantum computers in How Quantum Computers Will Work.