Faulty Chips Might Just be 'Good Enough' 342
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."
"Good Enough" (Score:5, Funny)
Re:"Good Enough" (Score:2, Funny)
oh yes, by all means (Score:5, Funny)
So they can remark them and sell them back to us...
Re:oh yes, by all means (Score:5, Funny)
I think you mean the 2.99999999th world...
FOOF (Score:2)
Or just sell them as Pentium Pros.
Re:FOOF (Score:4, Interesting)
Sounds like Radio Shack parts (Score:5, Funny)
Military Grade
Consumer Grade
Radio Shack
Re:Sounds like Radio Shack parts (Score:4, Interesting)
SB
Re:Sounds like Radio Shack parts (Score:5, Informative)
As well, there are a few off-axis surplus places (allelectronics.com, for example) that have super deals on things compared to the big suppliers, but less selection. Do you know a good surplus place? Add it to this thread!
Re:Sounds like Radio Shack parts (Score:4, Informative)
Re:oh yes, by all means (Score:5, Informative)
They mainly sell old stuff, almost all of it's used.
There's this company that they currently get most of their inventory from, let's call them company X.
Company X sells used parts too, they just do rigorous testing before they send them to customers, so a lot of it is marked "defective".
When company X marks something "defective", they pay to have it shipped to my friends' company. It's actually cheaper to do that than to recycle the parts, so my friends' company actually pays just a few dollars for a thousand pounds of equipment.
My friends personally go through all of the components, and put them through the extensive refurbishing process of blowing the dust off and inserting them into static bags.
They test it "good enough".. which entails making sure the computer boots up with that RAM and CPU. Maybe a 1 minute memory test on occasion. All in all, about 10% of everything they send out is worthless, and will be sent back by the customer in a week.
Re:oh yes, by all means (Score:2)
Already commonplace with RAM chips (Score:5, Informative)
Re:Already commonplace with RAM chips (Score:5, Informative)
don't forget that.
but the real reason for disposal i think is that throwing away at that early saves money from the manufacturers, like, it's much cheaper to throw away one chip than to throw away a tv that doesn't work good enough to be sold.
however.. what would be the good solution? maybe build the chips redundantly so that it wouldn't matter if one gate didn't work?
Re:Already commonplace with RAM chips (Score:2, Interesting)
Re:Already commonplace with RAM chips (Score:4, Funny)
You can RMA Windows XP?
Cool !
Already being done... (Score:5, Interesting)
Re:Already being done... (Score:2)
Re:Already being done... (Score:5, Funny)
Re:Already being done... (Score:5, Interesting)
i486 SX vs DX? (Score:5, Interesting)
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.
Re:i486 SX vs DX? (Score:5, Informative)
I remembered reading something like that so I dug out an old book of mine, "Upgrading and Repairing PCs" by Scott Mueller (2000):
Re:i486 SX vs DX? (Score:4, Interesting)
Manufacturer's do the same trick with speed grades. That's the principle reason why CPU's can often be overclocked beyond their rated maximum.
A more interesting thing about the 486SX/486SX is that the 487SX was, in fact, a complete 486. When plugged into the FPU socket, it disabled the 486SX entirely.
Intel claimed that the disabled FPU in the 486SX was only a temporary thing. Eventually, there would be a unique die for the 486SX and it wouldn't have an FPU at all. I kind of doubt this ever happened. The 486SX wasn't very popular.
Re:i486 SX vs DX? (Score:4, Interesting)
It did. By late 1991 the 486SX die was completely different with the co-processor removed.
Re:i486 SX vs DX? (Score:2)
If they could save die area, you can bet that they would have removed the FPU. The cost of any silicon chip is roughly proportional to the cube of the die area. (You can easily figure this out. Just consider that the cost per wafer and the number of defects per wafer are al
Re:Already being done... (Score:2)
Correction...
Digital Answering machines that use "reject" Ram chips that are not suitable for anything, because random dropped bits in a recorded message renders it discernible.
At least that's been MY experience with them. Dropped bits always occur when ever anyone relays important information like a phone number, time, pla
Old? (Score:2, Informative)
No Thank You. (Score:5, Insightful)
Re:No Thank You. (Score:5, Insightful)
If a CPU producer passed a general purpose chip, and it ended up that the defect was responsible for a tort, then they might be liable.
Their ought to be three bins: MIL-SPEC, No Defects, and Defect Detected But Passed Regression Suite. Anyone purchasing from the third bin has to accept liability for unforseen malfunctions.
Low cost solutions for the Military (Score:5, Funny)
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.
Re:Low cost solutions for the Military (Score:5, Funny)
I'm not so sure... (Score:5, Insightful)
It may seem that there's a basic linear line between over-the-top quality control and cost and more economical quality control and cost, however one has to think that if it turns out that these chips are more likely to have defects in them and in fact do in the future, how long will costs remain low? The chip will still be useless and will have to be replaced, added to that the cost of making the returns from the customer/store and then the possible customer dissatisfaction with the company's quality which could result in a lost sale in the future. Will it actually be cheaper in the long term?
Re:I'm not so sure... (Score:5, Insightful)
We've already got enough bad components floating around. We surely don't need any more.
Re:I'm not so sure... (Score:2)
Re:I'm not so sure...Expiration Date. (Score:2)
If small faults are tolerable (Score:5, Insightful)
The only reason for moving to digital switches was accuracy - the cost of the first digital bitflipper processors was far more expensive than valve technology was in 1950s and 1960s. And that really was the only reason for changing to digital processors.
Not quite (Score:5, Interesting)
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.
Re:Not quite (Score:2, Interesting)
Yes and no, depends how your operating the transistors. For example, ECL (Emitter-Coupled Logic) runs quite fast and doesn't saturate the transistors, contrasted to what TTL does. By not saturating they're able to switch states quite quickly, but they dissipate power like crazy. As of 7 years ago you could easily find ECL lines (For example this AND/NAND chip [onsemi.com] can work at least to 3 GHz. This is
Re:Not quite (Score:2, Informative)
Here's a short paper on how it's clocked:
Charge Recycling Clocking for Adiatbatic Style Logic [berkeley.edu]
Formica
Re:Not quite (Score:2)
It would probably be cheaper to use Pentium M or the lowest power Turion style chips than to switch to reversible logic. For the most part, PM and Turion chips are very close in performance with their desktop co
Re:If small faults are tolerable (Score:2)
Nothing new (Score:5, Insightful)
In short: computers suck...
Re:Nothing new (Score:5, Insightful)
I bought a friend an LCD and it had a single pixel fault - bright green always on right in the middle. Made the display unusable. Manufacturer pointed to their returns policy of 5 deal pixels and would not accept it back.
If the pixel had been at the corner - no problem.
Problem with looking for CPU failures is that there are a very large number of ways chips could fail - and for each of these you have to try and ascertain what the impact of the failure is.
It would be very hard to ascertain the myriad of impacts a single gate failure could have, let alone the combinations of multiple failures.
I would hate the manufacturers to create a second tier of CPUs at a lower price point - the ways these chips could cause my s/w to fail would be vexing.
Re:Nothing new (Score:2)
Chips can be tested while still on their wafer, along with the other 70 or so dies. Bad died do not need to continue through the manufacturing process. LCD displays have to be mostly assembled before they can be tested. There's a much larger cost associated per unit for LCDs
Re:Nothing new (Score:4, Insightful)
It would be nice to get one or the other though. Both flawed AND expensive is a real drag.
Caveats (Score:2, Informative)
Xilinx offer EasyPath [xilinx.com] option by testing for a customer-specific application. Customers use EasyPath customer specific FPGAs to achieve lower unit costs for volume production once
Already being done (somewhat) (Score:5, Insightful)
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.'
Re:Already being done (somewhat) (Score:2, Insightful)
Perhaps it's because Windows also tends to crash on normal machines too? I mean, you never hear *nix overclockers complain that their OS crashes all the time do you?
Re:Already being done (somewhat) (Score:2)
Yes? Although more normally it's things like gcc throwing tonnes of SEGV's and the odd bit of filesystem corruption. Maybe Windows just has more assert()s.
Re:Already being done (somewhat) (Score:5, Insightful)
For most chips, except ones like CPUs where you can charge a premium you don't speed bin (it costs lots of money), you pick a speed you think it should go at and toss the rest. Shipping chips that almost work is bad business - think about it, I make a $5 chip it gets put in a $100 product, if 10% of my chips don't work my customer loses $100 for every $50 he pays me, I have to get my failure rate down so it's in the noise as far as the customers are concerned, otherwise they'll go to the competition.
I think that the number of applications the original article's talking about where chip errors are tollerable are pretty small, suppose my CPU has a bit error in the LSB of the integer adder, the IRS may not care if my taxes are off by 1c, but the MSB is a different matter ("sir you appear to owe us 40M$"). On the other hand an LSB error is a big deal if the value you are dealing with is a memory pointer and breaks a program just as badly as if it is the MSB.
Finally a word about "metastability" - all chips with more than one clock (video cards are great examples" have to move signals between clock domains - this means that signals can be sampled wrongly (well designed logic should handle this) or in rare cases suffer metastability where the result causes unstable logic values to be latched into flops (usually these look like a value that swings wildly between 0 and 1 at a freq much higher the normal clock, a flop in a metastable state can 'pollute' other flops downstream from it turning a chip into a gibbering wreck. Now well designed logic doesn't do this very often, the flops chosen for crossing clock domains are often special anti-metastability flops used not for their speed or their size but their robustness - but the physics of the situation means that it's simply not possible to avoid - just possible to make it not happen very often. What you do need to do is figure out how often something will fail and pick a MTBF that is appropriate for your device ... I once found myself discussing this issue around a video chip we were designing and basically what it came down to was comparing the theoretical worst case failure rate (chip people tend to be very conservative, keeps us on the right side of Murphy) of our chip with Windows - our chip might fail once a year (and even then there was a pretty good chance you wouldn't notice it) while back then windows blue screen every day - would anyone notice? nope
Micron has done this for years with RAM (Score:5, Interesting)
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.
they don't waste finished chips (Score:5, Insightful)
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).
the FUTURE (Score:5, Interesting)
Re:the FUTURE (Score:5, Interesting)
Here is where you can make out like a bandit. Buy up a bunch of the revision which is hackable. Then, hack the ones you can and sell them as such. Then wait until supplies run out, and sell the ones where the hack failed on ebay. People will be on the lookout for the hackable version, and will pay a premium to get it from you. Oh, don't mention that you already tried it and it didn't work. They get exactly what they paid for, so this isn't dishonest in the least.
Actually, this happened to me. I wanted the Radeon 9500 with the ram in an L configuration, because you can soft-upgrade it to a 9700 most of the time. I bought one on ebay since there were no more on newegg. I specifically asked the guy "L shaped ram" he says yes. I get it and everything seems fine. UNTIL I lift off the heatsink. There, instead of a thermal pad or tape, is silver thermal compound. Clearly he had lifted the heatsink, and then put it back on when the hack failed. At least he was nice enough not to leave the hosed heat-tape on there. I ended up with a good upgrade for about what the newer revision would have cost anyway.
Now, in the next revision they just update the manufacturing to make it impossible to do the hack, because it is a nightmare for them to support all the half busted products that have been 'fixed' (even if they just say no, receiving and testing those products for the hack, and even phone support, costs like a bastard), and it cuts into the sales of the top tier products, where they make the highest margin. For chip companies this is as easy as dinging the faulty side of the chip before they assemble it completely, or putting some sort of "fuse" on the silicon itself, which they then burn out if that side is faulty. There is no way to take apart a chip to work directly on the silicon, and if there is and someone actually does it it will be a "Prove you can" since the equipment will be in the millions. (I can imagine a physics grad student with access to the machinery if they are doing superconductor or quantum computing research)
Re:the FUTURE (Score:3, Interesting)
Re:the FUTURE (Score:2)
Re:the FUTURE (Score:2)
Separating them will probably not be easy, much less repackaging them.
Processors? Or RAM? (Score:5, Funny)
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 >>
Re:Processors? Or RAM? (Score:2)
And most bank systems are lower cost than the voip head end stuff.
There is no way to limit where the junk ends up once its out the door and this looks like people have gotten so used to junk and flakey software that a few more bugs might not make any difference.
Not a good idea (Score:5, Interesting)
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..
Audible distortion and metadata (Score:5, Informative)
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 [jk0.org]. 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 [jk0.org].
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.
Faulty Chips (Score:3, Informative)
Re:Faulty Chips (Score:4, Informative)
Do we forget so quickly? (Score:2)
Now, in reality Celerons have a lower cache, lower bus speed and overall lower clockspeed. As I remember, because of this the core doesn't have to pass as high a standard as the current Pentium offering.
I'm sure there are others who would offer better knowledge on this.
Ati and nvidia do this already... (Score:4, Informative)
Lack of specification makes this hard to implement (Score:2)
OK until code is mixed with the data (Score:5, Interesting)
Something tells me that the manufacturers that use semi-defective chips are going to lose all their savings on product returns, warranty costs, and technical support. Given the low cost of most consumer electronics chips and the high cost of service labor, I doubt they will want the hassles of unreliable products.
A bit error here... (Score:5, Funny)
If'n it were possible... (Score:5, Insightful)
Please remember that this is the same industry that came up with the 80486SX when they were having lousy yields on 80486DX chips. If these processors had any utility, trust me, they'd find a way to make money off 'em.
Re:If'n it were possible... (Score:2)
Here's what you do: take three defective chips, glue them together so that they all run in parallel, and for each output pin, the pin's state is determined by "majority rule" of the three corresponding pins on the defective chips.
If it works for the space shuttle, it can work for your Radio Shack junk electronics.... the only inconvenient detail would be making this hack cheap/easy enough to be worthwhile...
Re:If'n it were possible... (Score:2)
Keychain (Score:2)
Pricing Structure Change (Score:2)
Good enough? (Score:2)
Stories (Score:3, Interesting)
Re:Stories (Score:5, Insightful)
Manufacturers are VERY aware they can charge a larger premium for better parts
Well there's a big difference (Score:4, Insightful)
However that's not true of the digital world. It is important that my processor gets the right answer to a calculation everytime, all the time. It is important that the data stored in RAM is always accurate. If any of these fail, well it can fuck things up and you can't predict what. Maybe it's the least significant bit of a sample in an audio file and I never know. Maybe it's a bit in the address of a jump in a driver interrupt and it brings the whole system crashing down.
So while I'm not really worried if all the resistors in my powersupply are precisely to spec because who cares if it produces 11.5v instead of 12v? I am VERY concerned that my CPU might give me anything ever but a completely accurate and predictable result.
Also, it can make a difference in the analogue domain too. The military is pickey for a reason. If a TV fails, no big deal. If an F16 fails, that's a big deal. However on a more mundane level you'll find milspec parts in use. I built a headphone amp using all 1% (or better) milspec resistors. Why? Well, they sound better. The design (metal film instead of carbon) has better audio characteristics, their resistance changes less with temperature, and the closer matched they are, the closer the output of the channels of the amp are.
Re:Stories (Score:2)
String him up by his balls... (Score:2)
Love the updated notice? Slashdot, you care to update yours to refelect this minor detail or do you just like playing along?
This is completely bogus. (Score:5, Insightful)
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.)
Re:This is completely bogus. (Score:2)
Re:This is completely bogus. (Score:2, Insightful)
Re:This is completely bogus. (Score:4, Informative)
There is another article here with some extra details. http://www.isa.org/PrinterTemplate.cfm?Template=/
Re:This is completely bogus. (Score:2)
Ah, right --- that makes a difference. (Do you remember the days when Wired had articles with actual technical content? <nostalge/>)
Hmm... I wonder if eventually we'll get processors with custom microcode to reroute around faulty subsystems?
This is also a problem in medicine (Score:5, Insightful)
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.
Ask Intel (Score:2)
People may not notice the problem, but if they ever find out it's there, they'll want it fixed, better to throw out a chip in the fab, than replace the product in the market.
Good Use (Score:2, Insightful)
The only way to TELL if they're "good enough..." (Score:2)
A chip is no good for ANYthing unless you know exactly what is wrong with it. It might not work AT ALL in a specific "audio application."
By the time you've tested a chip enough to characerize its defects, so that you know they are not going to interfere significantly with the very specific way it is used in a specific application, you've probably added so much cost that it's probably more expensive than a perfect chip.
In fact, you've gone away from the notion of "interchangeable part
Which is more wasteful? (Score:2)
It seems to me that the cost and energy going int
Fuck, no. (Score:2, Interesting)
And all manufacturing processes fail from time to time, microchip manufacturing is no exception. In a lot of 1000 chips, you might get 1 or 2 where the silicon wafer wasn't right to begin with, or one of the layers was a millionth of
Other news (Score:4, Funny)
Back in the Eighties... (Score:2)
Configurable compiliers & assemblers? (Score:2)
Lets say a CPU runs great, but fails on a coupla instructions. Why not just compile for it sans those instructions? For this to make any sense, there would have to be plenty of similarly flawed chips to work with though.
386SX anyone? (Score:2)
Probably not.. Yields are too good (Score:5, Insightful)
There have been moments in DRAM history when devices were made that were configured in some way during final test to work around bad spots. IBM did it for a while in the 1980s, I think. But with 90+% yields, it's not worth the added switching you need on chip to allow that. You could, in theory, use heavy ECC to tolerate a substantial defect rate. That's how CD-ROMs work, after all. But it's not necessary yet.
For a while, there was a market for DRAM with bad spots for use in telephone answering machines.
This is an idea that resurfaces periodically in the semiconductor history, but historically, the yields have always come up to acceptable levels.
Sinclair did this (Score:5, Interesting)
Old Computers Museum [old-computers.com]
quote: "To keep the prices down Sinclair used faulty 64K chips (internally 2 X 32K). All the chips in the 32K bank of RAM had to have the same half of the 64K chips working. A link was fitted on the pcb in order to choose the first half or the second half."
Remember, many of the best ideas have already been used.
No chance in heck this can work. (Score:3, Insightful)
Re:USC Idiots! (Score:2)
Gee, sounds like you flunked out of USC.
In any case, the idea isn't to put non-working components in your home computer. Instead, the goal is to use some rejected components for other uses where they can still succeed.
A good example is your favorite HDD. Does it have bit errors? Yep! But can you tell? Nope! Because the supporting hardware is able to detect and correct the errors without you ever knowing abo
Re:Keychains, eh? (Score:2)
Anyway, with the 1GB USB memory stick, LED mini-flashlight, office alarm system RFID tag and bottle opener on my key ring I don't think I have much room for anything else - oh yeah, there's a few keys on it too!
Plus, it's already being done. (Score:5, Insightful)
Depends...
Graphics chips these days have multiple pipelines, and are shipped in variants with different numbers of pipelines. If you can build a board that lets you use (say) any two pipelines out of a 4-pipeline chip, then you can use more of the defective chips. Similarly, if you're making MP3 chips, and their FM radio or LCD subsystems fail, you sell them to APple to put in the iPod Shuffle...
The thing is, defective chips are already sorted into bins like this. Processors are binned by clock speed... buy a low-speed CPU and it could well have come from the same run as its higher-speed cousin. Memory has mechanisms to allow for a certain number of bad cells. It wouldn't surprise me at all if some 2-pipeline GPUs are 4-pipeline versions that failed the 3rd or 4th pipeline.
I don't know how much headroom is left.