EMP and Stored Data

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  • #52354
    daaswampman
    Participant

    I recently read several articles related to how an EMP may effect stored data! It seems that the data could be corrupted even if the device survives!?!

    [snip]

    If you’re not using OPTICAL storage, all your data may be wiped out in a nuclear war, solar flare or EMP attack

    While more people are becoming aware of the risk of an EMP attack, what almost nobody seems to realize is that magnetic storage media is also subject to data loss from electromagnetic phenomena. This includes hard drives, RAID storage arrays, thumb drives and even SD cards.

    http://www.naturalnews.com/2017-04-26-if-youre-not-using-optical-storage-all-your-data-may-be-wiped-out-in-a-nuclear-war-solar-flare-or-emp-attack.html

    Magnetism and EMP

    Magnetism is a property of some materials. Magnetism is convenient for computerized data storage, because of the achievable high density, low latency, and possibility of multiple rewrites. However, this last property is also the bane of long-term storage: stored data can be affected by external magnetic sources, and is subject to gradual leakage. Even reading implies “grabbing” a bit of energy from the medium, thus weakening the data storage. Magneto-optical drives fare a bit better:

    The medium magnetism can be altered only at high temperatures; at room temperature, it is “fixed”.
    Reading can be done optically (because the medium optical qualities are modified by the magnetic orientation which was forced upon it when it was last heated), thus leaving the magnetic field “alone”.
    Although manufacturers of magneto-optical drives claim reliable storage for long durations (decades, up to a century or two), this heavily depends on environmental conditions, and has never been tested “in full size” since the technology itself is not that old.

    In particular, magnetic storage, whether magneto-optical or not, can be disrupted by applying a huge amount of magnetism in one go, something known as an Electromagnetic Pulse. This is the electromagnetic equivalent of a full stadium of beer-powered sport fans bellowing simultaneously (this has been used by some movie directors to obtain sound effects which are hard to simulate in a lab, resulting for instance in this scene — a cricket stadium was involved). The method of choice for generating big EMP is through nuclear weapons: nuclear fission and fusion emit huge amounts of high energy gamma rays, which, by colliding with electrons, create the EMP. EMP can also be generated with non-nuclear devices, albeit with a much lower energy.

    Hollywood, in its everlasting educational mission, has depicted a non-nuclear EMP in which the generating device looks like a jukebox. There has been some allowance for artistic license, though: a non-nuclear EMP works by rapid compression of a conductor in a magnetic field, where “rapid” means “high explosives”. While the EMP effect has some military applications in specific situations (especially disabling onboard electronics in missiles, without needing to actually hit the missile with another missile), the common wisdom is that the explosives are more a general threat than the EMP itself. Would-be terrorists would not care about electromagnetism; they would just blow up things with the explosives alone.

    A Faraday cage is effective against EMP proper; however, it does not block gamma rays and neutrons from a nuclear explosion, so gamma rays may enter the cage and generate a local pulse by interacting with the magnetic storage medium itself. The best protection for magnetic storage devices against a nuclear event is a deep underground bunker (it is also efficient for protecting human operators). That’s what they do for NORAD: the headquarters are buried under a mountain.

    https://security.stackexchange.com/questions/11333/most-secure-data-storage

    #63838
    TRex2
    Participant

    Stackexchange is usually a useful tool for learning about a subject, but keep in mind some of what is posted there is from people going beyond their true level of expertise. Some of those situations are present above.

    One thing I noticed is the following:

    A Faraday cage is effective against EMP proper; however, it does not block gamma rays and neutrons from a nuclear explosion, so gamma rays may enter the cage and generate a local pulse by interacting with the magnetic storage medium itself.

    Ummmm, No. The discussion is about an EMP, not a local nuclear explosion, and the gamma rays (and much more so, the neutrons) would have been attenuated long before they reached the Faraday cage, and are completely irrelevant to the discussion.

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