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Let's say I have some data on HDD that being only viewed. How long those areas of HDD will last in comparison to those which gonna be constantly overwritten ?

Andy D
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  • Are you asking about the longevity of the bits stored on the drive, or the media, itself (eg, wear out write capability or retention capability through rewrites)? – fixer1234 May 06 '18 at 21:53
  • @fixer1234 bits. – Andy D May 07 '18 at 00:06
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    Assuming you're speaking of SSDs, there are a couple very nice articles written about SSD longevity. While this is an older article, it is perhaps the best and most thorough: https://techreport.com/discussion/24841/introducing-the-ssd-endurance-experiment The article does not deal with RO vs RW data types, but instead addresses the real-world measurements of bit-life in consumer SSD drives. – music2myear May 07 '18 at 21:33

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I believe a more appropriate way of asking this question might be "How long does bit rot take to set in".

The answer is "It entirely depends entirely on the disk", however in reality the hard drive is orders of magnitude more likely to fail from old age then for bit rot to occur.

On any decent hard drive in a normal operating environment, bitrot should not set in for many years - typically longer then the 1-5 year warranty of the drives. While it certainly does happen, for a home user its more of a theoretical then real problem.

davidgo
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As mentioned here:
"Most sources state that permanent magnets lose their magnetic field strength at a rate of 1% per year. Assuming this is valid, after ~69 years, we can assume that half of the sectors in a hard drive would be corrupted (since they all lost half of their strength by this time). Obviously, this is quite a long time, but this risk is easily mitigated - simply re-write the data to the drive."

Andy D
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  • Interesting, but isn't this logic flawed - It would seem to make the assumption that the 50% of the magnetic strength is a key figure, and I would imagine that that figure is not correct. Also, I'm not sure a platter could be cosidered a permanent magnet. – davidgo May 07 '18 at 04:01
  • @davidgo why wouldn't you follow the link and discuss that with the author of answer ? – Andy D May 08 '18 at 01:51
  • That answer is from 2011 from a user who was last active in 2015 - you were the one who sited it as credible in your answer. (An interesting post from arnaudk at https://bytes.com/topic/software-development/answers/851490-magnetic-decay-modern-hard-drives suggest what to me sounds like a more credible mechanism for how data is stored, further invalidating an already suspect claim) – davidgo May 08 '18 at 04:02
  • @davidgo thanks, could you summarize those it you answer ? – Andy D May 08 '18 at 17:32