Big Data - Hardware - CENTRAL PROCESSING UNIT

The term "CPU" has had two meanings in computer hardware. CPU is used to refer to the plastic and steel case that holds all the essential elements of a computer. This includes the power supply, motherboard, peripheral cards, and so on. The other meaning of CPU is the processing chip located inside the plastic and steel box. In this book, CPU refers to the chip. The speed of the CPU saw dramatic improvements in the 1980s and 1990s. CPU speed was increasing at such a rate that single threaded software applications would run almost twice as fast on new CPU versions as they became available. The CPU speedup was described by Gordon Moore, cofounder of Intel, in the famous Moore's law, which is an observation that the number of transistors and integrated circuits that are able to be put in a given area doubles every two years and therefore instructions can be executed at twice the speed. This trend in doubling CPU speed continued into the 1990s, when Intel engineers observed that if the doubling trend continued, the heat that would be emitted from these chips would be as hot as the sun by 2010. In the early 2000s, the Moore's law free lunch was over, at least in terms of processing speed. Processor speeds (frequencies) stalled, and computer companies sought new ways to increase performance. Vector units, present in limited form in x86 since the Pentium MMX instructions, were increasingly important to attaining performance and gained additional features, such as single- and then double-precision floating point. In the early 2000s, then, chip manufacturers also turned to adding extra threads of execution into their chips. These multicore chips were scaled-down versions of the multiprocessor supercomputers, with the cores sharing resources such as cache memory. The number of cores located on a single chip has increased over time; today many server machines offer two six-core CPUs. In comparison to hard disk data access, CPU access to memory is faster than a speeding bullet; the typical access is in the range of 10 to 30 GB/sec. All other components of the computer are racing to keep up with the CPU.