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revolution
When all else fails, read the source


Joined: 24 Aug 2004
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Location: In your JS exploiting you and your system
revolution
Usage has no effect upon the electron leakage. You can be reading it continuously and it can suddenly change state, or you can have it powered off and it will still change state.

10 years is the figure stated in the flash chip spec documents. If you were to refresh the data each 10 years then you get another 10 years of retention. So for a device with endurance of 100,000 writes you could potentially get 10 years * 100,000 = 1 million years but you have to keep refreshing it to get that type of life.

However: Beware. Nowadays the flash chips commonly guarantee 100,000 writes for the first block only and the other blocks are guaranteed for one write. The control software is expected to swap out the failed blocks and replace with other blocks. So if the controller software (internal in the device) keeps lots of spare blocks for swapping upon failure then it can potentially extend the life a lot, but you still risk the block becoming unreadable without being detected since the devices do not have scrubbing algos. The ECC may be able to correct, but having to rely on that is not such a nice way to do things.
Post 25 Jan 2010, 02:50
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Borsuc



Joined: 29 Dec 2005
Posts: 2466
Location: Bucharest, Romania
Borsuc
I don't think the Google report is of any use to normal users since they use high-end HDDs which cope well under stress and temperature -- I could buy that but they tend to be more expensive, some a lot more expensive... so their report does not have much meaning on normal users' hard drives...

also you guys may want to check this

http://www.wizcode.com/articles/comments/flash_memory_fragmentation_myths_and_facts

@revolution: can you please give me some sources for the leaks in flash memory, if you can still find it like you did before. I'd like to do some research on it, thanks! Smile

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Post 25 Jan 2010, 19:51
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 17467
Location: In your JS exploiting you and your system
revolution
Borsuc wrote:
I don't think the Google report is of any use to normal users since they use high-end HDDs which cope well under stress and temperature -- I could buy that but they tend to be more expensive, some a lot more expensive... so their report does not have much meaning on normal users' hard drives...
How do you know that? I thought they used standard commercial drives. Which is why the report was important and meaningful for everyone.
Borsuc wrote:
@revolution: can you please give me some sources for the leaks in flash memory, if you can still find it like you did before. I'd like to do some research on it, thanks! Smile
Just download the flash memory specs from any maker. BTW: MLC is even worse for longevity and endurance than the SLC, but you would never be able to know which chips are in your drive without some very deep investigation.
Post 25 Jan 2010, 23:00
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Borsuc



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Borsuc
revolution wrote:
How do you know that? I thought they used standard commercial drives. Which is why the report was important and meaningful for everyone.
I think they fall under "server" drives. Those are made to cope very well under stress (and thus high temperature). They are standard commercial drives, I didn't say they can't be found in standard markets. I could have purchased one, but it tends to be more expensive -- sometimes a lot more expensive.

Plus I don't stress it much at all since most of the time I use the ramdisk (HDD only for reads mostly or one-write sessions, 5-6 secs depends). So I don't need to spend 3-4 times the amount to get a server HDD Laughing

They usually fall under the "server" or "enterprise" sections in online stores.

revolution wrote:
Just download the flash memory specs from any maker. BTW: MLC is even worse for longevity and endurance than the SLC, but you would never be able to know which chips are in your drive without some very deep investigation.
While I did not find anything related to 10 years leakage, from a Toshiba spec it did say that they have a designed life of 5 years or so (obviously no detail is given, just marketing bullshit)... and yeah they did say MLC has less longevity. Smile

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Post 26 Jan 2010, 19:36
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 17467
Location: In your JS exploiting you and your system
revolution
Borsuc wrote:
While I did not find anything related to 10 years leakage, from a Toshiba spec it did say that they have a designed life of 5 years or so (obviously no detail is given, just marketing bullshit)... and yeah they did say MLC has less longevity. Smile
Many manufacturers quote it as a "data retention" parameter. Some even claim 40 years, but most that I have seen are 10 years. 5 years is very short IMO, I've never seen that before.

[edit]
BTW: Just in case it was not clear, I am referring to the flash chip specs, not the SSD drive specs. Just wanted to make sure that was clear.


Last edited by revolution on 26 Jan 2010, 19:50; edited 1 time in total
Post 26 Jan 2010, 19:47
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Borsuc



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Borsuc
Well it was talking about portable device flash drives Razz (I would guess mini devices and such, cellphones w/e)
Post 26 Jan 2010, 19:48
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