HDD SMART codes, better explained

HDD SMART codes, better explained - where?

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First post, by Snayperskaya

Posted on 2016-01-12, 20:07

Snayperskaya Offline

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I've always wondered if there was, somewhere, a good, technical and in-depth explanation of SMART values. I've read some 10s of sites with just the basics, but I'm sure there's more to it. Example: There's no clear distinction between 05 (Reallocated sector count) and C4 (Reallocated event count), and I've seen cases where a C4 is generated without a 05 (not that it should happen, but the code's description is very similar so one would expect that).

Reply 1 of 3, by Tetrium

Posted on 2016-01-12, 21:08

Tetrium Offline

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I don't know for sure, but couldn't it just be because different manufacturers implemented SMART differently? And maybe even different drives of the same manufacturer used different settings.

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Reply 2 of 3, by Snayperskaya

Posted on 2016-01-12, 21:49

Snayperskaya Offline

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Yes, each mfg can choose which codes they will implement on their SMART subsystem, but some of them are present on a wide variety of models. I think those are implemented on similar ways, even if the threshold is different. A list with vendor-specific values and their explanations would be great, too.

Reply 3 of 3, by dexter311

Posted on 2016-01-12, 22:37

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The Wikipedia page has a pretty comprehensive overview: https://en.wikipedia.org/wiki/S.M.A.R.T.

As for the difference between 05 and C4, 05 is the total number of bad sectors which have successfully been remapped to the reserve area, while C4 is the number of ATTEMPTS to remap bad sectors (including both successful and unsuccessful attempts). Obviously if the raw value for C4 is higher than 05, your drive is in very bad shape because the drive is trying to remap bad sectors but can't.

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