<html><head><title>A chip for your PC</title></head><!--(c) G.C. '97, '98 A.R.R.-->
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<center><h3>A chip for your PC</h3></center>
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 The original microprocessor used in computers known as <i>IBM compatibles</i>, the 8086, was slow, but it appeared to be very good in those days; now, it is a different matter.
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 The problem is that the 8086 and, so, all the derivatives, down to the Pentium IIs, are just too complicated: it was a CISC (Complex Instruction Set Computer) chip: the 8086 provides over one hundred different instructions, but each is fairly specific; within the chip, these instructions are broken down into more simple instructions and it is these basic commands which the chip deals with using logic circuits; in a way, x86 machine code is an interpreted language and the chip is thus microprogrammed with an interpreter, which has to be pretty slow. RISC (Reduced Instruction Set Computer) chips, on the other hand, perform a small set of instructions very rapidly, because their instruction sets are much more like those basic instructions executed in CISC chips, producing much greater performance than CISC chips. The ARM is such a processor: it has only around twenty five instructions, although they are very general, and the processor directly executes these with logic circuits i.e. the chips is hardwired.
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 However, the legacy of the original Intel CISC collection is that the modern PC processors too follow the same architecture. I recently read, in a PC user's magazine, that the processors of today had come a long way from the crawling pace of the original 8086 chips; actually, this has a fairly weak basis in fact, because the Pentium IIs, even with their MMX, are still based on 8086 CISC architecture, with finer tracks, bundled together, which would be fine, if the original 8086 chips had been designed for expandability; unfortunately, like most things in the DOS world, as the popularity of the PC grew beyond the expectations of the original producers, they maintained backward compatibility by cramming extensions onto a processor which had not been designed with expandability in mind, increasing the CISC characteristics of the processor. The perfect example is the 386: this introduced 32-bit technology and still supported all the old 16 and 8-bit operations, causing the instruction set to balloon!
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 PCs continue to get faster, not through advanced technologies, but through sheer chip size compression. The 486 second processor chips for the Acorn RiscPC needed to be plugged in away from the ARM chip, because PC microprocessors dissipate so much heat; the environmentally-friendly Energy
Star standard, which is given to PC chips running with low energy consumption, has an energy consumption boundary three times that of the energy consumed by ARM chips; the new StrongARMs can even be powered through 2 AA batteries and remain cool in operation, while PCs are constantly overheating. You would do well to remember that supercomputers are supercooled, to improve performance: an overheating processor just slows it down.
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 The PC chip appears to be new, advanced and complicated; it is simply getting smaller and hotter, without room for expansion. There have been recent television adverts, proclaiming that, for a good computer, all you need do is ensure that <i>the Intel Pentium II processor is inside</i>; those same adverts proclaimed that you'd be getting <i>the most advanced Intel technology available</i>, but now that they own the StrongARM and the Alpha, that simply isn't true.
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