Mad Dog 21/21: Flea Circuits
May 3, 2004 Hesh Wiener
A couple years ago, when Midge and Madge were still with us, Professor A.G. Gertsacov played Times Square with them. Midge and Madge were trained fleas, whose efforts may have inspired the semiconductor industry’s chip monks, people who usually feel quite differently about bugs. Intel, IBM, and their ilk have always itched to make their chips smaller, to be sure, but lately they are itching to grab headlines about their plans to, like fleas, jump ahead.
Intel is moving toward production of all its processors at the 90 nanometer line size, a big reduction from the 130 nanometer lines of the prior fabrication generation. IBM is well on the way to that milestone, too, as are other companies in the chip business. Even as they shrink circuit geometry to 90 nanometers, they are looking ahead. They want to make their products even tinier, and then do it again. They want to leap ahead like fleas.
Fleas, at least the more nimble ones, are the long-jump champions of the insect world, able to traverse distances 150 times the length of their own bodies. So, even though they cannot fly, they sure know how to get around.
Chipmakers, by contrast, may characterize their every step as a leap, but they advance in more measured and deliberate steps than a flea. When they don’t, they can land where they are not prepared to land. Critics say that Intel’s Itanium, which wags refer to as “Itanic,” was one such leap, moving Intel away from its established 32-bit architecture even as it pushed the company forward into 64-bit territory. Now Intel says it will be adding some 64-bit capability to its line of 32-bit chips, in part because it can do so affordably as its chip geometries become smaller.
In the meantime, Intel’s arch-rival, Advanced Micro Devices, has taken a bite out of the processor opportunities offered by Hewlett-Packard, drawing blood with its Opteron, a circuit that bridges the 32-bit and 64-bit worlds. HP was the first server maker to say it would become a host for Itanium, and agreed to participate in the chip’s development process. HP has stuck with its commitment (especially for its HP-UX Unix variant), but neither HP nor Intel has leapt to the forefront of the server market as a result. And now HP is selling two-way and four-way Opteron servers for Windows and Linux operating systems. HP is jumping around quite a bit.
Fleas not only leap forward by great lengths but also hop to impressive heights. Entomologists say they can go as high as 80 times their body height. But they don’t always look before they leap. This propensity to hop first and think afterward is one basis of the taming process used by ringmasters recruiting bugs for duty in a flea circus. Professor Gertsacov has explained that putting a flea in a container with a lid, so that it bops its little flea head when it leaps too high, is the first step in what would be called, if a flea were a horse, “breaking it.” After a while, and with some other efforts that are the professor’s trade secrets, a flea becomes pretty docile.
The same cannot be said of circuits that fly too high. Circuits that are overclocked can go into a runaway state and ultimately suffer permanent damage. The amount of heat a chip generates is the same as the power it consumes. That is, essentially all the power consumed by a chip is dissipated as heat, which must be drawn away. The heat is generated, for the most part, by switching and by leakage. The steady state current flow through a CMOS processor is comparatively small (although the current required to bring all the capacitance in a chip up to working voltage when the chip is turned on may not be). But a processor that is not switching is not doing any work, so engineers who want their circuits to do a lot of work have to come up with ways of getting more computation with less heat.
One technique commonly used to give chips a little more processing headroom is cooling. Manufacturers prefer to use air cooling, usually with forced air but sometimes based on spontaneous convection, because it’s cheaper in the first place and is easier to maintain than alternatives, but lots of very fast computers use liquid coolants. PC overclockers, among others, also use Peltier effect coolers, to allow them to push chips to very high speeds.
But miniaturization turns out to be one of the best ways of making chips faster without having to worry about meltdowns or putting lithium batteries on the path toward explosion. Smaller circuits can run at lower voltages, usually have lower leakage current, and often provide dramatic reductions in total power dissipation. This, naturally, tempts engineers to increase clock speeds and to put ever more circuitry on a single chip, because the processor business doesn’t just sell more of the same in a smaller package, it sells more of everything in a smaller package.
Chip engineers are hardly alone when they strive to increase the amount of work their chips can perform. Flea circus operators similarly seek strong performers: healthy fleas that can pull up to 80 times their own body weight. Harnessed by tiny threads to wagons or attached to other props, circus fleas perform feats of strength that are impossible for other creatures. Moreover, they do their work without consuming very much fuel, which, in the case of fleas, is blood. Every couple of weeks, Professor Gertsacov feeds Midge and Madge with his very own blood, but not directly. He has developed a system involving a drop of blood and a petrie dish that keeps his performers healthy without putting himself at risk. Flea bites can itch and, in fact, involve saliva, which is both an irritant and an anticoagulant, the very mixture that gets a host to serve up a fast meal.
But the Midge and Madge who performed in Times Square have gone on to better things. This is not so hard to do if you work in Times Square. It was inevitable, as human fleas (Pulex irritans) live for maybe two years, which turns out to be much longer than cat and dog fleas do. Fortunately, for kids of all ages itching to see a flea circus, Midge and Madge have been replaced by understudies, another two girl fleas, also named Midge and Madge. This fortunate coincidence has enabled Professor Gertsacov to keep his circus poster budget as small as his performers.
Why females? Well, in the flea world, the women are bigger, which makes them easier to see, to say nothing of their being stronger. And, to keep his roster of employees from growing so large that they bleed him dry, Professor Gertsacov must confine his cast to a single gender.
Whatever Midge and Madge may lack in the way of flea companionship, they still manage to live luxuriously, particularly when they are on the road. They travel in a tiny replica of an Airstream trailer that is lined with fur.
Packaging can be as important to chipmakers as it is to fleas. In the case of Intel, the company’s latest demonstration of miniaturization comes in the form of a PC that has all its components (except for a keyboard) buried in a flat screen. The screen’s stand includes a carrying handle. The machine, named Florence, giving it the gender of Midge and Madge, is not yet a product but rather a concept machine, showing what Intel’s customers might want to produce using the chipmaker’s technology.
IBM has its own miniature computers to show off, including one model made by its Japanese arm that can fit in a pocket. The androgynous Core, which uses a Transmeta chip, includes a processor, memory, and disk, but must be plugged into a base station that has a keyboard, a display, and various connectors to be used. The whole idea is convenience. Users who now may move around with a laptop, PDA, or flash memory gizmo will be able to take a whole environment on the road, as long as there’s a base station at the other end of the journey.
By the time computers like these Intel and IBM concepts get to the market, they might be just as powerful as today’s somewhat bulkier computers, or even faster. Unlike laptops, these two computers don’t need to be throttled down to save power. If they can be built so they won’t overheat, which is more of an issue for the IBM pocketsize Core than the Intel Florence, there is no reason why they can’t run at whatever speed the chipmakers can deliver. They won’t be involved in a trade-off between speed and battery bulk, the way laptops and PDAs are.
Still, there is no guarantee these computers and their less glamorous thin blade cousins in the server world will appear as soon as the chipmakers might wish. Unlike flea circus impresarios, chipmakers must be sure all the bugs are out of their concepts before going to market. So while Professor A.G. Gertsacov and his Acme Flea Circus, featuring Midge and Madge, will definitely be at the Piccolo Spoleto Festival in Charleston from June 2 through 13, Florence and Core are still waiting in the wings.