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“Moore’s Law affects us from the time we get up in the morning till we go to bed at night,” says Roger Espasa, director of Intel Barcelona (based at the UPC’s North Campus) and a professor in the Computer Architecture Department. But most people are unfamiliar with the law formulated by Gordon Moore, who earned a bachelor’s degree in chemistry from the University of California at Berkeley and a PhD in chemistry and physics from the California Institute of Technology, and who was one of the co-founders of Intel. In the 1970s he predicted that the number of transistors that could be put on a chip would double every 18 months, resulting in a doubling of the processing speed of computers every year and a half.

“Computers are made of integrated circuits or microprocessors. These microchips, in turn, contain components called transistors, which can be seen as analogous to cells, with the circuit corresponding to the human body in the comparison. According to Moore’s Law, the number of transistors that fit on a silicon microchip doubles every 18 months, which translates into an improvement in computer performance. The task of engineers working on computer architecture is to turn transistors into performance,” explains Àlex Ramírez, a professor in the same department as Espasa and the coordinator of a research group in the computational sciences unit of the Barcelona Supercomputing Center – Centro Nacional de Supercomputación (BSC-CNS).

According to both Espasa and Ramírez, “the main point to emphasize about Moore’s Law is that it’s not a scientific law derived from observation of nature that’s always fulfilled, like Newton’s law of gravity, for example.” In fact, it’s an observation made by Moore that has driven computer architects and the semiconductor industry that makes computer chips “to develop and manufacture transistors that match the pace predicted by the law,” Ramírez explains. “For the last 30 years, the law has been fulfilled every 18 months without fail, and every year and a half end-users have found they’re being offered more capacity, better performance, or lower energy consumption on the same amount of silicon,” says Espasa.

 

According to Ramírez, “the miniaturization of transistors has driven Moore’s Law.” The ability to put an ever greater number of transistors on microchips has made it possible to progressively increase the speed, amount of memory, and calculating capacity of computers. The more transistors manufacturers put on a chip, the more memory it has. Ramírez illustrates this trend by pointing out that “the first PCs back in the 1980s had just 512 K of memory, while a cell phone now has 32 Mb.”

But will it be possible to stay on the track predicted by Moore’s Law indefinitely? The fact is that the law eventually comes up against certain limitations. For example, if the number of transistors is greatly increased, there is also a steep rise in power consumption.

“When the speed of computers is doubled, power consumption increases by a factor of four,” says Ramírez. Moreover, computers heat up, which is why fans have been developed to cool them. One of the challenges over the next few years will be to increase computer performance while cutting energy consumption.

“There will be a lot of pressure to produce computers that have the same capacity but consume less. We’ll have to reduce power consumption for both economic and ecological reasons. If computers use less power, electricity bills will be lower, which will be good for companies and users. A lower environmental impact will be another benefit".

So far Moore’s Law has always been fulfilled, but it is calculated that with the current technology, known as CMOS (complementary metal oxide semiconductor), it will cease to hold around 2020-2025. “If no alternative is found to existing technology, Moore’s Law may soon run out of steam,” says Ramírez. CMOS is based on circuits that are fabricated on a silicon substrate to which metal layers are added. These layers are oxidized to make them semiconductors (i.e. so electrical current does not always pass through them).

According to Ramírez, “it’s not clear what might happen in the future. Special-purpose processors—used to execute one specific program—may appear. An example would be a chip used only to play music. This isn’t feasible at present, though.”

Fortunately, as in the case of renewable energies, a concerted effort is being made to find alternatives. The world’s three leading manufacturers of transistors are conducting research on replacement technologies. According to Espasa, these technologies include carbon nanotubes, which will replace the transistors currently used when further miniaturization is impossible, and a new kind of memory known as PCM (phase change memory), which will be denser and faster than the flash memory currently in use. In the case of PCM, prototypes already exist.

An effort is also being made to keep scaling according to Moore’s Law by increasing the number of cores in microprocessors. These devices currently have four or eight cores (a core is a central processing unit or processor). But within the framework of a project known as Larrabee Intel is designing a microprocessor that will have 32 cores (i.e. a chip with 32 processors). Intel and the UPC are conducting joint research and collaborating on this development, which will enable new visual applications, such as 3-D video games and animation.

This line of research is likely to provide users with access to technology that is increasingly visual, intuitive and easy-to-use, because a single silicon chip will perform many more functions. The breakthrough will pave the way for 3-D video games and has already led cell phone manufacturers to consider incorporating 3-D in their devices. It will also serve as an enabling technology for XML3D, which will allow users to post 3-D videos online, and for the first 3-D cameras and TVs.

In the meantime, “the alarm clock rings in the morning thanks to this law, which is also the reason why chips, radios, elevators, car brakes and power steering, the computers at work, and our social networks function.” So it’s well worth taking a moment to learn more about Moore’s Law.