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(BQ) Part 2 book "Modern operating systems" has contents: Multiple processor systems, security, case study 1 - linux, case study 2 - windows vista, case study 3 - symbian os, operating system design, reading list and bibliography. | 8 MULTIPLE PROCESSOR SYSTEMS Since its inception, the computer industry has been driven by an endless quest for more and more computing power. The ENIAC could perform 300 operations per second, easily 1000 times faster than any calculator before it, yet people were not satisfied with it. We now have machines millions of times faster than the ENIAC and still there is a demand for yet more horsepower. Astronomers are trying to make sense of the universe, biologists are trying to understand the implications of the human genome, and aeronautical engineers are interested in building safer and more efficient aircraft, and all want more CPU cycles. However much computing power there is, it is never enough. In the past, the solution was always to make the clock run faster. Unfortunately, we have begun to hit some fundamental limits on clock speed. According to Einstein’s special theory of relativity, no electrical signal can propagate faster than the speed of light, which is about 30 cm/nsec in vacuum and about 20 cm/nsec in copper wire or optical fiber. This means that in a computer with a 10-GHz clock, the signals cannot travel more than 2 cm in total. For a 100-GHz computer the total path length is at most 2 mm. A 1-THz (1000-GHz) computer will have to be smaller than 100 microns, just to let the signal get from one end to the other and back once within a single clock cycle. Making computers this small may be possible, but then we hit another fundamental problem: heat dissipation. The faster the computer runs, the more heat it generates, and the smaller the computer, the harder it is to get rid of this heat. Already on high-end x86 systems, the CPU cooler is bigger than the CPU itself. All 517 518 MULTIPLE PROCESSOR SYSTEMS CHAP. 8 in all, going from 1 MHz to 1 GHz simply required incrementally better engineering of the chip manufacturing process. Going from 1 GHz to 1 THz is going to require a radically different approach. One approach to greater speed is through
