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.This continues thepattern of the Pentium claiming the headline figure for speed.However,on balance, the Athlon is, by most tests, slightly faster than the Pentium.An update.That was written yesterday.This morning came the news that Intel hasburst through the 3 GHz barrier (just) with a 3.06 GHz device.This,they say, includes hyper-threading, a technique that involves splittinga program into units that can be ran simultaneously.It allows the microto run multiple applications at the same time, with the processorappearing to be two processors.Such multitasking is available inWindows XP and Linux and probably all their successors.So wheredoes this leave the future, are we going to go for greater and greaterspeeds, or will we develop multi-tasking so we effectively have greaterand greater numbers of micros sharing the work? I have a feeling thattask sharing will be the answer.It seems likely that Intel is now back out in front.Exciting times ahead.196 The Athlon XPAnother update.Almost immediately, Athlon has replied with what appears to beanother significant step forward  64-bit computing.The microprocessor which as yet has been living with the codename Hammer will be sold as the more user-friendly name of  AMD Athlon64 and will be available in mid-2003 and will join the PowerPC 970in the  64 club.It will be able to run 64-bit, 32-bit and 16-bitapplications without any speed penalty and so avoid the cost of buyingnew software.The only technical information that is included in the initialannouncement is a new bus system using  hypertransport technologywhich AMD claims to increase throughput by 50% over existingdesigns.Intel will have something to say about that claim, I expect.The clock speed of the first batch will be little different from the XP,around the 2.8 GHz, but the design will provide more scope fordevelopment and will be able to run programs at a higher speed.Really exciting times ahead.over 3 GHz clock speeds, 64-bitcomputing and multiple instructions being carried out simultaneously.Sounds good.The desktop speed Olympics is shared between the PowerPC 970,Pentium 4 and the Athlon 64 whereas the computer market isdominated by the IBM clones leaving just a minor role for thePowerPC 970 in the Apple-Mac.As we saw earlier, the result of anyspeed test does depend on the nature of the test.Having said that, andat the risk of irritating the fans of each, in the race for the overall speedfreak the Athlon 64, when it is available, will appear to be the winnerwith the other two virtually shoulder to shoulder a pace behind.But itdepends on the test chosen and we know that any speed king will bedethroned so very quickly.A (very) approximate comparison based on the currently availableinformation is shown in Table 14.1.Table 14.1PowerPC 970 Pentium 4 Athlon 64Clock speed 2 GHz 2.8 GHz 2 GHzBus speed 900 MHz 533 MHz 533 MHzBits 64 32 64Process size 0.13/ 0.09 microns 0.13 microns 0.13 micronsOp systems OSX IBM linux Windows WindowsComparative speed 1988 1984 2372Max memory Terabytes 40 GB Terabytes197 Introduction to Microprocessors and MicrocontrollersQuiz time 14In each case, choose the best option.1 Compared with the Pentium 4, the Athlon XP designhas:(a) faster FSB, running at 533 MHz.(b) the same speed of FSB.(c) slower FSB, running at 333 MHz.(d) faster FSB, running at 2.8 GHz.2 As the Pentium 4 and the Athlon XP are both using0.13 micron technology:(a) it does NOT imply any other similarities between thedesigns.(b) they will both run at the same clock speed.(c) they will have the same number of pins.(d) the cache sizes are equal.3 The three floating point execution units in the AthlonXP simultaneously handle store and load, multiplyfunctions and:(a) SIMD functions.(b) add functions.(c) divide functions.(d) 3D NOW! functions.4 When Branch prediction is correct it:(a) increases the overall speed of running the program.(b) increases the length of the pipeline.(c) decreases the clock speed.(d) prevents overheating of the microprocessor.5 The Athlon Instruction cache has a capacity of:(a) 256 kB.(b) 32 bits.(c) 64 kB.(d) 384 MB.198 15Microcontrollers andhow to use themGetting ready for takeoffIn the 1960s, electronics started to awake from its slumber that hadused thermionic valve technology that was recognizably similar tocircuits that had been built for thirty years.The pace of progress wasgentle.The first semiconductor material was developed and thetransistor came into use in just a few years [ Pobierz całość w formacie PDF ]

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