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• #5 JoeYi őstag JoeYi #1

  Új Válasz 2016-02-29 13:41:48 #5

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  JoeYi

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  megtaláltam: ha 5%-nál több szektorhiba va negy chipen akkor letiltja a vezérlő. Viszont nem jelent teljes halált, csak méret csökkenést (sőt van olyan márka amelyiknél van beépítve tartalék chip amire ilyenkor átirényítódik az adat):

  "The drives in our study consider a chip failed if more than 5% of its blocks have failed, or after the number of errors it has experienced within a recent time window exceed a certain threshold. Some commodity flash rives contain spare chips, so that the drive can tolerate a bad chip by remapping it to a spare chip. The drives in our study support a similar feature. Instead of working with spare chips, a bad chip is removed from further usage and the drive continues to operate with reduced capacity. The first row in Table 5 reports the prevalence of bad chips. We observe that around 2-7% of drives develop bad chips during the first four years of their life. These are drives that, without mechanisms for mapping out bad chips, would require repairs or be returned to the vendor. We also looked at the symptoms that led to the chip being marked as failed: across all models, around two thirds of bad chips are declared bad after reaching the 5% threshold on bad blocks, the other third after exceeding the threshold on the number of days with errors. We note that the vendors of all flash chips in these drives guarantee that no more than 2% of blocks on a chip will go bad while the drive is within its PE cycle limit. Therefore, the two thirds of bad chips that saw more than 5% of their blocks fail are chips that violate vendor specs."

  Plusz érdekesség hogy a chipeknek hivatalosan 2% szektorhiba felett kellene blokkolódnia, de csak 5%felett teszik, kis gyártói trükközés

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