peja81
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Pojavio se Samsung 840, verzija od 120GB navodno već može da se nađe za oko 11000 dinara, koristi TLC čipove koji su deklarisani na 1000 P/E ciklusa, tj. na 1000 upisa što ne mora da predstavlja problem u praksi, ali ovako na papiru deluje malo nezgodno zato što je uobičajena vrednost 3000-5000 ciklusa. Više o tome:
http://www.anandtech.com/show/6337/samsung-ssd-840-250gb-review/4
http://www.anandtech.com/show/6337/samsung-ssd-840-250gb-review/4
Ako je ovo tačno onda nema potrebe brinuti o radnom veku TLC-a.However, there is actually more to SSD endurance than just P/E cycles and write amplification. There has been a lot of talk lately about digital signal processing (DSP) in the industry, which is supposedly the solution for lower endurance NAND.
The basic idea behind DSP is very simple: you read changes in voltages and adapt to the changes. As I mentioned in the previous page, the voltages change as the NAND wears out and if your controller can't adapt to the changes, you'll be stressing the NAND even more. Each time you're trying to program or erase the cell, you are wearing it out, so you don't even have to succesfully program or erase the cell to cause damage. That's why the guess and test process for writing to NAND is so harmful; it may take multiple tries and each try will wear out the NAND even more.
However, if your controller can read the changes in program and erase voltages, you will know what voltages to use to program/erase the cell. Even though DSP doesn't make NAND immortal, it causes a lot less stress on the NAND, allowing it to last for more P/E cycles than what you would get without DSP.
Again, it's hard to give out any specific numbers of DSP usefulness in real world, but for example STEC is claiming that their CellCare technology can extend the endurance of regular 3K P/E cycle MLC up to as much as 60K. I've heard unofficial figures as high as 100K for some companies' DSPs, but I would take all figures with a grain of salt until they are tested by a third party. Either way, even if a good DSP is only able to double the endurance of NAND, it's a huge deal as we move to even smaller process nodes and possibly even more bits per cell.
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