Engineers Devise a Technique To Fight Counterfeit or Recycled Smartphone Memory (ieee.org) 52
Flash is designed to last a decade or more of use. A lot of the gadgets that rely on it, however, are not. Shady recyclers have spotted opportunity in that mismatch, stripping out used chips and selling them as new. But fret not, there is something that can be done to address the issue. From a report: Engineers at the University of Alabama have come up with a straightforward electronic examination that can tell if a flash chip is new or recycled, even if that chip has only seen 5 percent or less of its life. And the technique is so straightforward that a smartphone app could run it on its own memory. [...] A flash memory cell is like an ordinary transistor, it has a source and a drain and a channel through which current flows under the control of voltage on the gate electrode. The difference is that the gate is split into several layers -- the control gate, the blocking oxide, the floating gate, and the tunneling oxide.
[...] Voltage on the control gate causes electrons to tunnel through that bottom oxide and get stuck inside the floating gate. This charge or its absence is the stored bit. It alters how much voltage you need to turn the transistor on in a way that you can easily measure. Erasing the bit is done by reversing the voltage and driving the charge out of the floating gate. Ray and his team took advantage of the rather high voltages -- about plus or minus 20 volts -- needed to program and erase flash. The more you program and erase a cell, the more defects will accumulate in the oxide, he explains.
[...] Voltage on the control gate causes electrons to tunnel through that bottom oxide and get stuck inside the floating gate. This charge or its absence is the stored bit. It alters how much voltage you need to turn the transistor on in a way that you can easily measure. Erasing the bit is done by reversing the voltage and driving the charge out of the floating gate. Ray and his team took advantage of the rather high voltages -- about plus or minus 20 volts -- needed to program and erase flash. The more you program and erase a cell, the more defects will accumulate in the oxide, he explains.
A more productive solution? (Score:4, Insightful)
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"Productive" in terms of efficient use of resources? Likely yes. Productive in terms of vendor lock in and maximising corporate profits? Not so much.
Corporations don't want effectively recycling, they want to have vendor lock in and to be sure they're getting paid.
Shit like this isn't about you, it's about them.
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Productive in terms of vendor lock in and maximising corporate profits? Not so much.
There isn't really a difference. If recycling has higher overhead than new sourcing, then it decreases profits over buying new chips. If it has lower overhead, then it increases profits.
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You realize we're talking about bog standard SD cards?
The vendor locking ship sailed years ago. IIRC even Sony is using standard flash.
We all know you're just repeating derp you heard somewhere else.
Why devise ways to prevent recycling? (Score:3)
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I guess part of the question is - when you measure flash degradation over time, is it linear? If yes, then 5% is not that big a deal. If no, then 5% current wear might indicate it's about to fall off a cliff.
Decent Summary (Score:2)
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No one has a problem with reusing, it's selling a used item as new that causes problems.
How much wear and tear actually exists? (Score:4, Insightful)
I suspect that a lot of this used flash would still outlast the expected lifespan of the device for most people. I can even see the recycling companies using this technique themselves to sell the recycled chips in different bins based on use. The article doesn't describe the extent to which people are getting worn out flash memory, and I suspect it's not a particularly big issue.
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When the OS runs out of RAM it just starts killing apps.
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I'm not an expert but I believe flash memory in phones isn't used for paging. The reason in precisely that it would severly impact on the lifetime of the device's internal memory. When the OS runs out of RAM it just starts killing apps.
Not so much because paging would kill the flash, but because paging in and out would kill performance. It turns out to be much better to just kill apps not used for a while when low on RAM, especially since all mobile apps already have to be written to assume they can be evicted at any time.
The only sort of paging I've seen used in any Android device, at least, is paging to compressed RAM (zram). This generally isn't a huge win, though it sometimes makes sense.
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Thanks for the comment. I give it more credibility coming from someone who's been involved in a mobile OS :).
I don't work on anything directly related, but I got curious a while ago and asked people on the Android kernel team who do exactly this stuff. So you're getting it secondhand, but originally from authoritative sources. Assuming I didn't screw it up, which can never be completely discounted :-)
Do a few write and erase cycles.... (Score:2)
And the memory is used. With 100% confidence!
Do write and erase until it is broken and you know have many cycles it had left.
Time to break out the heatable flash (Score:1)
Apparently you can reset the flash cells' use count by adding circuitry that does a heating thing. Those can be safely recycled, and the problem with re-used flash sold as new goes away.
And maybe we should start and design the devices to last a bit longer than we currently do, too. My nokia 6310 is still going strong (needs new rubber and new battery), and I see no reason to replace it. Why aren't we even trying to make designs that good? Instead all you get is stupid little gimmicks like rounded corners or
Re:Time to break out the heatable flash (Score:5, Insightful)
Because having phones that last longer is in direct conflict with the motives of literally every competitor making phones. Even if they never sit in a room and collude they'll reach the same result simply by acting out of self-interest. Why would they compete with each other on more durable phones or in any real way on cost when those things hurt their bottom lines? Better to make everyone replace their phone on a regular basis and compete for pieces of the next round of purchases.
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"Why aren't we even trying to make designs that good? Instead all you get is stupid little gimmicks like rounded corners or notches in the screen." Because having phones that last longer is in direct conflict with the motives of literally every competitor making phones. Even if they never sit in a room and collude they'll reach the same result simply by acting out of self-interest. Why would they compete with each other on more durable phones or in any real way on cost when those things hurt their bottom lines? Better to make everyone replace their phone on a regular basis and compete for pieces of the next round of purchases.
Er, for the same reason that all consumer products don't disintegrate in just one day?
If they go too far in planned obsolescence, then they leave themselves wide open to a competitor who does not.
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The market wouldn't bear that, that is the only reason and for markets where it will that is exactly what they do (see paper towels).
"If they go too far in planned obsolescence, then they leave themselves wide open to a competitor who does not."
It is far more profitable to operate as they are. They get most of the market purchasing phones 5x more often this way, they make as much getting 20% of those upgrades as they wou
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Apple does this so that you will pay their inflated prices for commodity flash memory.
You can pick on Apple but the reality is that a lot of manufacturers do this, they're not charities.
If.... (Score:1)
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Because sometimes it doesn't. More often than new flash fails. But the used parts are not disclosed to the consumer.
Apples says that any 3rd party repaied Counterfeit (Score:2)
Apples says that any 3rd party repaid in now an Counterfeit apple device
Elephant gun to ... (Score:2)
... kill a piss ant.
"Memory" vs. "storage" (Score:4, Informative)
How nice it would be if at least technical sites such as Slashdot could get straight the difference between memory/RAM and SSD/flash storage.
Re: "Memory" vs. "storage" (Score:2)
It's an arbitrary difference so Slashdot (ie. people better informed that you) doesn't care. SSDs are commonly refered to as "flash memory". They evolved from EEPROM technology. You know what ROM stands for, right?
When talking about "memory" and "storage" the context is more important than the words themselves.
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It wouldn't matter as much if there wasn't a big difference when it comes to 'memory' and 'storage'. They both remember stuff, but the modern terminology has made the words analogous for Dynamic RAM and Static RAM. DRAM suffers almost no wear and tear from usage and is designed to change state until thermal breakdown occurs. SRAM is typically implemented with components that suffer wear and tear.
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I think you got the terms mixed up with "volatile" and "nonvolatile" memory.
DRAM = capacitors store bits.
SRAM = logic gates store bits.
They are both volatile (i.e. bits are lost when power is off.)
SRAM typically has no wearout mechanism. There are "nonvolatile" SRAMs that have an EEPROM component to it that will have the normal EEPROM wearout mechanism. Aside from such corner cases they're not much different from the logic gates that implement the rest of the chips in the system.
Flash is a refinement on t
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PROM is a write once memory that is basically a fuse for every bit. Blow the fuse and it is now permanently stored for life.
EPROM is the one where UV light through the window erases everything back to all ones, ready for some new writes.
Re: "Memory" vs. "storage" (Score:2)
It's always been confusing. Your BIOS is stored in ROM, so it's a type of non voletlie memory which is really storage. CDs were more fully referred to as "CD-ROM" which implies that they're memory, even though they're storage. EPROM is also a type of storage; the basis of present day "flash memory", which is also storage.
There's never been a clear-cut differentiation in how we use the terms "memory" and "storage", which is why we keep having these silly discussions. It all depends on the context. From
Re: "Memory" vs. "storage" (Score:2)
As a CSE who graduated almost 30 years ago, I can take a stab at explaining the historical difference between memory and storage and also why some of the technologies have strange names.
Your explanation was excellent, so thank you for that, but I wasn't confused about the actual difference between the concepts. I was pointing out that the terminology is confusing because the line between memory and storage can be rather fuzzy at times. Your statement that flash is "memory with a storage interface" just makes that more apparent. It's a great description, but it also perfectly illustrates why we often use the terms interchangeably.
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Re: "Memory" vs. "storage" (Score:2)
How does your appeal to gerontocracy wave away the fact that "memory" has always been used for certain types of storage?
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Why limit your complaint to Slashdot? 36.5 million results for flash memory [google.com].
They're all wrong. Because it couldn't possibly be you...
Recycled electronics from China is good stuff (Score:2, Informative)
Due to the wonders of the internet you can go on Ali Express or Ebay and order all sorts of electronic wonders from china REAL cheap. If you're a maker or a hobbyist you've got more available to you than ever before, for fractions of a penny on the dollar of what it used to cost 10 years ago.
When you order certain things that /should/ be pricy but are not more often than not you get something that contains recycled pulls. IGBTs, relays, things that come as packaged "modules" for integration - Like GPS modul
no doubt sponsored by Apple (Score:2)
The new iphone update will contain a routine to brick the iphone if it was repaired. After all, why would people buy new iphones if they could simply repair their old ones?
Smartphone app can't do this (Score:4, Insightful)
The notion that a smartphone app can do this test doesn't hold up to scrutiny. I don't think even the operating system could do it in most cases.
Both of the techniques described require the testing tool to be able to measure the effects of wiping or rewriting a given page. But modern flash hardware doesn't provide any way to operate on a specific physical page, only on logical pages which the hardware reallocates to different physical locations. Pretty much any time you try to erase a block of flash, what the hardware will really do is give you an already-erased block.
And, of course, apps don't have access even to logical blocks, they have to work through the file system. File systems designed for flash add another layer of shuffling, and even general-purpose file systems often do some amount of reallocation.
Is there anything fundamentally new in this? (Score:2)
Flash erase wear-out, especially at low temperatures during the erase cycle, has been well-known for many years. I first encountered this circa 1991, during qualification of Intel 28F010 NOR flash for an extended temperature application. And again during qualification of AMD flash to replace this, because Intel had many months of production gap due to a botched fab move to a partner fab (Nippon Steel, I believe), that turned out to be incapable of producing the device.
Disturb during write is also well-