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Faulty Chips Might Just be 'Good Enough'
Ritalin16 writes "According to a Wired.com article, 'Consumer electronics could be a whole lot cheaper if chip manufacturers stopped throwing out all their defective chips, according to a researcher at the University of Southern California. Chip manufacturing is currently very wasteful. Between 20 percent and 50 percent of a manufacturer's total production is tossed or recycled because the chips contain minor imperfections. Defects in just one of the millions of tiny gates on a processor can doom the entire chip. But USC professor Melvin Breuer believes the imperfections are often too small for humans to even notice, especially when the chips are to be used in video and sound applications.' But just in case you do end up with a dead chip, here is a guide to making a CPU keychain."
If ever a story was appropriate for Slashdot.
Don't throw away those "almost perfect" CPUs! Give them to needy people in the third world!
So they can remark them and sell them back to us...
Now before I get modded down, I be to remind whoever might read this that what I am saying is FACT. - bogaboga
And for a long time so. "Audio RAM" is the euphemism.
If I remember correctly, digital answering machines use "reject" RAM chips that aren't suitable for data storage, because minor dropped bits in a recorded message aren't discernible.
I'd rather my chip works as advertised.
Actually, the supercomputers used for warfare and conflict analysis at the Pentegon and the CIA use these rejected chips.
In addition, they are used in the so-call "Star Wars" missle defense system prototype.
Although these chips don't actually work, the results are often good enough for their purposes.
LCD manufacturers routinely put defective screens on the market, on the premise that a dead pixel here or there "won't be noticed". Too bad, because consumers do notice and do tend to return the product equipped with the dodgy screen, only to be told that it's "normal".
In short: computers suck...
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
The CPU vendors are already doing a 'sort and grade' operation, when they label processors. Have been for years. When the yield from the fab is lower-grade, the dies get packaged and labelled as lower-speed parts.
Then the Overclockers come in and ramp the speed back up, and claim 'the faster chips are a ripoff' and complain that 'Windows is always crashing.'
Micron started a group over 15 years ago that tests RAM chips at all stages of production that fails testing.
When I worked there it was called the "Partials Division". This group invented the "audio ram" market. They have a wide ranging sorting and grading process. It is called "SpecTek" I believe now. I sometimes see low end memory modules with SpecTek Ram.
12 years ago, I was production technician in a Surface Mount Assembly division that shared a building with Partials. We used to assemble memory modules and even video cards that used "PC grade" chips from the partials group. Everyone said they were good enough, but personally I have always steered clear of them.
The last year I was at Micron, we had a lot of discussions with NEC, Intel and some Russian Fabs to provide the same services to them. We tested a couple million chips from these companies in tests. Never did hear what the end result was.
Many of the chips fail inspection prior to going into the package, and then some more fail functional test after that. Probably more than half the price of a chip is the factory itself and the R&D work which is amortized over so many zillions of parts, and much of the rest is all the handling, packaging, shipping, and middlemen. I'd guess less than 10% is per-part materials and labor.
Therefor throwing away a $2 chip during production doesn't cost $2. It's only worth $2 by the time the customer pays for it.
Sure you could sell the defects at some discount, but it's only worth the trouble for some high volume part like RAM where defects are easily useable, and definitely NOT a part where the impact of some particular defect in the end user's application could be really hard to characterize (like a CPU).
In the FUTURE, single core processors will be dual core processors where one side didn't pass quality control. Someone will eventually figure out how to hack the chip to use both halves anyways, and the market will be flooded with cheap dual core chips that don't always work. Remember, you read it here first.
Unknown host pong.
I can see it for RAM, but for processors, I don't think so.
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Though, you would probably have to make sure that certian important data for an audio or video clip are stored in *good* memory. Or else you could run into problems where a clip doesn't know where to end.
But, what are the odds that a null terminator gets messed up in meao90efghijklmnopqrstuvwxyz{|}~ÇüéâäàåçêëèïîìÄÅÉ
<<ERROR: Unexpected EOF >>
There is a reason for throwing out those chips! Maybe it's true that _most_ human ears wont notice that the least significant bit has been flipped in a über-noisy phone recording for a digital answering machine, but what if it was the most significant? That would make an audible "pop".
Ok, so maybe for non-critical equipment in the "use-and-throwaway" category. But this will not bring us cheaper hardware, just less functional hardware. Those chips are _literally_ going nowhere slow.
If you've ever had to debug something that turned out to be flaky hardware, you KNOW it's a PITA. If anything, awareness should be increased when it comes to the really cheap brands. They aren't always very stable, but people sometimes go for the cheapest RAM anyway, and then complain to ME when it doesn't work. There actually is some connection between what you pay, and what you get. Argh.
I'm done rambling now, thanks for waiting..
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While I agree that analog processors probably hold some promise, there is one large issue with them: heat. A major reason why processors get hot in the first place is that after each cycle the state is returned to a neutral position, which usually means grounding the gates to discharge them. This waste energy has a large conversion over to heat. Analog processors can really be thought of digital with multiple states, instead of two. This means that while more work can be done, there is larger values of charge to disapate.
What has always had my curiousity for why it has not been seemly worked on is "reversable" chips. There are essentially two sets for every mechanism and the system toggles back and forth. The discharge of the old system is used to drive the new mechanism; thus, a lot of wasted discharge is conserved for reuse. Reversable chips are reported to generate far, far less heat. I have heard that Intel and others know about this, but it is simply a better immediate investment because consumers are happy paying for the current line of toasters.
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We've already got enough bad components floating around. We surely don't need any more.
The other version was that the coprocessor had the highest failure rating for the chip fabrication. So on these chips with a failed copressor, the coprocessor was turned off, but the rest of the chip was still usable.
I vaguely remember this whole practice was described in a computer book my friend was reading, because I remember a joke the author told about computer salesmen. Unfortunately I only remember the joke, not the useful info from that book. (This joke comes from the days of small computer shops)
Q : What's the difference between a computer salesman and a car salesman?
A : The car salesman knows when he's ripping you off.
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Basically, the problem is this. With mechanical and analogue devices, most of the time you know that if you change the inputs a small amount, the outputs will change a small amount.
But digital devices are chaotic. Change one bit in the input, and the output is likely to be radically different. One bit in the wrong place on a Windows system can make the difference between Counterstrike and a BSOD.
You can use substandard devices for some applications; dodgy RAM, for example, can be used to store audio on, and it would work just as well for video framebuffers. But you could never put anything programmatic on it; that has to be perfect.
(IIRC, they do recycle faulty wafers. One of the ways is to scrape the doped layer off and turn them into solar cells. I don't know if they can use them again for ICs, though.)
If you go and buy a handful of 5% resistors, you will find ~0 that are within 2% of their value - if you buy 2%, none w/in 1%, etc...
Manufacturers are VERY aware they can charge a larger premium for better parts
If you look at what the "big ticket" items are in the US economy, electronics and medicine are up at the top of the list.
And the reason for this is, as you get closer to perfection, it takes more and more of an economic cost, in terms of money or resources or time or effort. For a computer or a medicine to go from 90 percent to 99 percent utility means a ten fold increase in price.
Thats why the constant quest to have "perfect" electronics and medicine is driving up the prices of these things to the point where normal people can't afford them. If we could accept that we didn't always need new, perfect, shiny medicines and electronics, it would put them in a sane price range.
Hopefully I didn't put any [] around my words.
Second, even if all the bits of the sample are wrong, an answering machine probably samples at 8k Hz. If one sample has the wrong value, then the pop will be 0.125 milliseconds long, so not really that bad.
A single sample error will sound like the click in this wave. But many digital answering machines use lossy compression optimized for the periodic sound of the human voice. A bit error in one of those may spread out over a whole speech packet, producing audible pops like in this wave.
In addition, even if the audio storage is lossy, there would need to be either a second certified defect-free part to hold metadata where in memory each message starts and ends, or an error-correcting code applied to the metadata.