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Replace magnetic with optical

Discussion in 'Electronic Basics' started by Radium, Apr 3, 2007.

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  1. Radium

    Radium Guest


    Why do hard disc drives use magnetic discs?

    Since non-volatile flash RAM chips are not yet feasible for HDD-
    substitution, why not replace the magnetic platters with optical ones
    that use 400 nm lasers to write, read, erase, and re-write data?

    Optical platters using 400 nm lasers would surely have advantages over
    magnetic platters. More data per area and less vulnerability to
    environmental magnetic disruptions -- to name a few.

    I say dump all magnetic discs and replace them with the optical
    equivalent. Use 400 nm lasers because 400 nm is the sweet spot between
    shortest wavelength and non-ionizing radiation. Shorter wavelengths
    require less size to write/read data. Too short and you increase your
    risk of cancer. So use 400 nm and dump those useless magnetic discs.

    Red lasers -- used by CDs -- are horrible because they require so much
    space on the disk to write data. Green lasers -- used by DVDs -- are a
    tad better. Blu-ray -- at 405 nm -- is almost at the best wavelength
    but not quite!


  2. Yum, looks likr I get first bite. >:)
    Possibly because decades ago, there were no blue laser diodes?
    It's been tried, but I'll not try to pr-empt the words of those who know
    far more history than I do. As to volume, a single platter of a hard disk
    can hold a few hundred GB. There is an optical disk being developed that is
    said to have more, but I don't think it's on sale yet. Current blue diode
    disks don't hold anything like this much. Multiply by four or so, per
    layer, but not by a hundred.
    Less soze, no, as I said. Less time? Definitely not. And if you spun an
    optical disk as fast as a hard disk, the laser would have to be extremely
    strong to write to the surface it as it passes by so rapidly.
    If you can find a green laser in a DVD, and prove you found it, grab that
    time machine with both hands and patent it before anyone else gets there
  3. kony

    kony Guest

    High data density and speed, leveraging mature technology
    incrementally updated for reasonable cost effectiveness.

    They are, but it'd cost a lot. Too much mostly because Bill
    Gates & Co. let windows become so bloated it now needs
    Gigabytes of space, but the other software manufacturers are
    to blame as well.

    Is what you have in mind as cheap and fast? Usually optical
    is not.

    What makes you think a "magnetic disruption" is a
    significant problem? What makes you think there is any
    less vulnerability at all? A hard drive has a GREAT deal of
    mechanical movement, other devices meant for lesser read and
    write cycles might be viable if cheap enough, small enough,
    and fast enough, but if only more expensive, no smaller and
    no faster, the one thing you assume is not a clear victory.
    You seem unable to use current technology if you find it
    such a problem. Thus, if we introduced this tech you want,
    you would be as likely to just find it a problem and pretend
    you have an advanced insight on some other thing that isn't
    here yet either, only a hypothetical device which in
    practice may also have drawbacks.
    Forget ideals and focus on real needs. The market doesn't
    really need a concept drive they need something proven
    through years of testing. That at an attractive price
    point. Eventually there will be more optical alternatives
    but it would be foolish to "dump all magnetic discs" before
    the replacement technology is ready.

    Your ideas are akin to "cars suck, dump all cars and use
    space ships", but wordier.
  4. John  Larkin

    John Larkin Guest

    (snipped everything)

    Optical drives are way too slow, way too low capacity, and not as
    reliable as hard drives.

    Flash is too expensive and has write endurance problems. Write a block
    a couple hundred thousand times (like a directory block) and it dies.

  5. Radium

    Radium Guest

    So a magnetic disc will have a higher capacity and speed than an
    optical disc of the same size?
    Is this due to overheating of circuits?
  6. CBFalconer

    CBFalconer Guest

    Not so. To prove it to yourself, go out and buy a 200 odd gig hard
    drive. Rip it open, and discard all parts other than the rotatable
    disk(s) itself. Now compare its volume with that of a DVD disk,
    which holds maybe 8 gig.
  7. Bob Willard

    Bob Willard Guest

    You don't need permission from me -- or from Bill Gates -- to do so.

    You may need to hack the OS a bit to boot/run from the DVD of your choice,
    which is easier with a *NIX than a WinWhatever. Then boot from and run
    from that DVD, and report back on how fast it is, relative to the
    normal HD you will then be wanting back. Oh, and make sure you use a
    PC with limited RAM, to feel the effects of swapping to your DVD.
  8. Not quite a fair comparison. A double sided double layer DVD can hold
    around 20 GB. A similar blu-ray (405 nm) disc could hold 5 to 10 times
    that. A holographic memory of the same volume could hold much more.

    And when is the last time your harddrive was affected by an "environmental
    magnetic disruption" short of an EMP from a nuclear blast? :)

    --- sam | Sci.Electronics.Repair FAQ:
    Repair | Main Table of Contents:
    +Lasers | Sam's Laser FAQ:
    | Mirror Sites:

    Important: Anything sent to the email address in the message header above is
    ignored unless my full name AND either lasers or electronics is included in the
    subject line. Or, you can contact me via the Feedback Form in the FAQs.
  9. LaserUser

    LaserUser Guest

    I wonder why no one has commented on him (original topic starter) that he
    saying they use green lasers for dvd.
  10. Bob Myers

    Bob Myers Guest

    Now you've done it, Sam...Radium will be after us now re his
    latest and greatest fantasy, the holographic-storage laptop. And
    it will be entirely YOUR fault....

    Bob M.
  11. Two people have, at least. Doug and me. How are you accessing usenet? How
    many posts do you see in this thread?
  12. Pat B.

    Pat B. Guest

    Cant find info now but last year radium was found to be FOS. Instead
    of Radium he should be called Random.
  13. It's actually closer than you think. :)

    --- sam | Sci.Electronics.Repair FAQ:
    Repair | Main Table of Contents:
    +Lasers | Sam's Laser FAQ:
    | Mirror Sites:

    Important: Anything sent to the email address in the message header above is
    ignored unless my full name AND either lasers or electronics is included in the
    subject line. Or, you can contact me via the Feedback Form in the FAQs.
  14. Lord Garth

    Lord Garth Guest

    Actually, I did think about that one...I just felt it was like a waste of
    effort to
    submit a correction.

  15. It doesn't matter what you tell him, he's a troll.

    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
  16. Radium

    Radium Guest

    In which the holographic-storage laptop is fully laseronic and does
    not require electricity to any extent, but instead, is powered by a
    remote nuclear fusion reactor.

    Instead of electronic chips, this PC contains laseronic chips [laser
    circuits instead of electric circuits]. No magnetism, no electricity.
    Just 400 nm lasers power by a long-distance Deuterium-Tritium reactor.
    All storages devices are solid-state. No discs, no tapes. Everything
    is purely hardware. There is no microcoding. Everything is hard-wired,
    except for the RAM chip. The laseronic RAM chip acts as a solid-state
    HDD. Windows 98 SE is the OS and Mozilla 1.8b is the browser and,
    Creative Music Synth is the MIDI synth.

    Last but not least, all the lasers use a wavelength of 400 nm.

    quotes from :

    "Each machine instruction (add, shift, move) was implemented directly
    with circuitry. This provided fast performance, but as instruction
    sets grew more complex, hard-wired instruction sets became more
    difficult to design and debug."

    I still prefer the "hard-wired instruction sets"

    "a bug could often be fixed by replacing a portion of the microprogram
    rather than by changes being made to hardware logic and wiring."

    But I still perfer the "hardware logic and wiring".

    Yup. Just for personal preference, I also like my PC to be massively-

    The power supply starts off as a high-power 400 nm laser that is
    pumped by D-T fusion at a power station. As the laser light runs to my
    home, it does not do so at full-blast -- that would mean total
    destruction in everything in the path of the laser. Instead this
    gigalaser is used to power smaller less intense 400 nm lasers, these
    lasers are less intense but powerful enough to energize my photonic
    PC. Withing the PC itself, the intensity of the 400 nm laser light are
    much less still, just like the electric voltages in conventional PC
    are much lower in the motherboard, HDD, and other devices, than the
    110 volt socket with takes in the initial electricity.
  17. contrex

    contrex Guest

    Radium reminds me of certain bright, but uninformed, ten-year-olds
    that I have met. Is there a possibility that he has some kind of
    condition? Like being autistic or having development issues, or just
    being a snot-nosed little prick?
  18. danek

    danek Guest

    "no magnetism, no electricity" = no light

    P. Danek
  19. And plenty of fish to take the bait.
  20. Bob Myers

    Bob Myers Guest

    The smart money at this point seems to be on the

    Bob M.
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