Re: Has your memory card ever worn out?

Discussion in 'Digital Cameras' started by Soundhaspriority, Jul 21, 2012.

  1. Memory cards use NAND flash, which is a very strange medium. When NAND is
    used in a memory card, it is written only in large blocks; individual
    addressing is not possible in this application. The illusion that a single
    address can be rewritten is provided by rewriting the block.

    NAND cells are inherently unreliable. When a block is written, there almost
    CERTAINLY will be errors. The user does not see the errors because the block
    is written using a very robust error correcting code.

    Nota bene: flash is an unreliable physical device, with clever engineering
    used to provide the appearance of a reliable end user device.

    NAND is pattern sensitive to READ disturbance. When cells nearby are read
    [sic], it actually disturbs the reliability of the cell, which should, in
    theory, be rewritten at intervals.

    Consumer NAND flash now uses MLC (multi-level-cell) architecture, which has
    a much shorter lifetime than what used to be the gold-standard, SLC (single
    level cell.) SLC is now available only for enterprise apps. The short cell
    lifetime is allegedly disguised by wear-leveling algorithms, but when the
    block error rate exceeds the ECC capability, and READ disturbances
    occur...who knows?

    All this might be too complicated for the microcontroller embedded in a
    flash device to handle reliably. With flash, clever engineering created a
    problem that isn't simple. But the consumer needs flash. Providing it at a
    price the consumer is prepared to pay has resulted in a product that doesn't
    fail predictably. Predictable wear out has been replaced by catastrophic
    failure, as the rule, rather than the exception.

    In some cases, a memory requirement can be addressed by either flash or hard
    drive. In the case of a Sound Devices 744T, I chose to stick with the hard
    drive. My personal "feeling", which I can't substantiate with any hard info,
    is that some hard drives, selected for both make and particular model, and
    handled and mounted to avoid mechanical shock, are more reliable than flash
    alternatives.

    Bob Morein
    (310) 237-6511
     
    Soundhaspriority, Jul 21, 2012
    #1
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  2. Soundhaspriority

    Guest Guest

    nonsense. flash is significantly more reliable than hard drives.
     
    Guest, Jul 21, 2012
    #2
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  3. Soundhaspriority

    David Taylor Guest

    As far as I know, never. Mind you, during th years I've moved on from
    30 MB CF cards, through 512 MB CF, to 1 GB SD and up to 8 GB SD, so
    maybe I've never used one card enough to wear it out. I don't write
    much video though.

    David
     
    David Taylor, Jul 22, 2012
    #3
  4. Soundhaspriority

    Bruce Guest


    The only memory "cards" that have given me problems were Micro Drives.
    They were miniature hard drives, originally made by IBM but later sold
    on or possibly licensed to other manufacturers. I think they were
    used in the original Apple iPod.

    They were fitted into a case that was the same size as a Compact Flash
    card but about 50% thicker. Most, but not all CF-compatible devices
    could use them. They were extremely troublesome. I had about eight
    in all and all except two failed.
     
    Bruce, Jul 22, 2012
    #4
  5. Soundhaspriority

    Joe Kotroczo Guest

    On 22/07/2012 18:23, Bruce wrote:

    (...)
    Nah, the iPod used 1.8 inch hard disks. Micro Drives are 1 inch hard disks.
     
    Joe Kotroczo, Jul 22, 2012
    #5
  6. Soundhaspriority

    Bruce Guest


    Thanks.
     
    Bruce, Jul 22, 2012
    #6
  7. Soundhaspriority

    Guest Guest

    nope.

    the original ipod used 1.8" hard drives, which are still used in the
    current ipod classic.

    the ipod mini used microdrives, and because apple got a very good deal
    on them, many people bought an ipod mini for its microdrive because it
    was *cheaper* than buying the microdrive by itself. the empty ipod mini
    carcasses were later sold on ebay.

    the ipod shuffle was the first ipod to use flash, followed by the ipod
    nano which replaced the ipod mini, and later the ipod touch, which is
    an iphone without the phone.
    nope. a microdrive was a standard compact flash type ii card.
    yes they were troublesome. it used to be said if you dropped one, don't
    bother picking it up because it probably no longer works.
     
    Guest, Jul 22, 2012
    #7
  8. Soundhaspriority

    Savageduck Guest

    Yup!
    I still have a functioning Hitachi 2GB Microdrive which came with their
    PCMCIA adaptor.
    The current use I have found for it is to load it with MP3's and use it
    as a media device via the chrome covered PCMCIA slot in the dash of my
    Mercedes E350 (found directly below the volume control knob) most
    Mercedes owners have no idea that it exists.
    Quite neat actually. It also works if I use my old sub-1GB CF cards.
    Beats the hell out of burning CDs.
     
    Savageduck, Jul 22, 2012
    #8
  9. Soundhaspriority

    Arny Krueger Guest

    Current data suggests easily twice as reliable.
     
    Arny Krueger, Jul 23, 2012
    #9
  10. Current data suggest easily twice as reliable.

    Under what conditions?

    I'm about to buy a new computer, and will almost certainly use flash memory
    for the boot drive. But I guarantee there will be nothing on that drive that
    has to be continually re- or over-written.

    All the user-created files will be on a conventional hard drive -- unless I
    can be convinced that flash drive is sufficiently reliable.

    Of course, I create a bootable copy of my current computer's drive every one
    to three weeks, and keep intermediate copies of important files on a Zip
    drive. I also periodically back up all user data to an external hard drive.

    By the way, my Seagate hard drives are warranteed for five years and have
    given me no trouble. Name a consumer flash drive that has that long a
    warranty.
     
    William Sommerwerck, Jul 23, 2012
    #10
  11. Soundhaspriority

    Neil Gould Guest

    Interesting. What OS are you using that guarantees no re-or over-writing?
     
    Neil Gould, Jul 23, 2012
    #11
  12. Soundhaspriority

    Alan Browne Guest

    Pretty hard for the "boot" (system) drive to avoid being written on as
    the system operates.
    If you don't back up to two external locations your data means nothing
    to you.
    The warranty on the Seagate drives is meaningless. When the drive fails
    you get another drive. Big deal. You don't get your data back and that
    is typically many more times valuable than the drive.

    I've yet to hear of a MacBook Air user having issues with their flash
    disk. The MBA has been out there for over 4 years - and it only had 64
    GB of SSD making it a candidate for early failure (due to the wear
    leveling management).
     
    Alan Browne, Jul 23, 2012
    #12
  13. Soundhaspriority

    Whisky-dave Guest

    It's an intresting point as you could have 2-3 backps to hard drivs for the cost of one SSD.
    What about swap files and temp files such as caches for browswers and the like.
    I think it is, but that's not the reason to choose between Hard and flash drives. SSD are chosen because of their speed nothing else, in fact some even use more power than conventional drives so for laptop use make sure you have a low power one.

    Aren't ZIP drives the least relible ....
    I have 3 ZIP readers only one still works, not using ZIP as backup since 2005.

    I'm not sure SSDs have settled down as HD have in that most HD are pretty much the same, but there;s differnces with SSDs there's cheap consumer and teh more relible faster SSDs, they aren't the same.
    I used to see server HDs that spun at 10,000 rpm not sure what spec SSDs might be used to repalce them.
     
    Whisky-dave, Jul 23, 2012
    #13
  14. I'm about to buy a new computer, and will almost certainly
    READ WHAT I WROTE!
     
    William Sommerwerck, Jul 23, 2012
    #14
  15. Of course, I create a bootable copy of my current computer's
    Do you mean outside the house? If so, point valid and taken. If that isn't
    what you meant, READ WHAT I WROTE.

    Why do people insist on reading what they think is there, rather than what
    actually is?

    You didn't answer my question.

    Well... Mac Book Air owners don't actually /do/ anything with their
    computers. They just carry it around to show off, and occasionally some
    piddly thing with it.
     
    William Sommerwerck, Jul 23, 2012
    #15
  16. Soundhaspriority

    Neil Gould Guest

    MY RESPONSE WAS SPECIFICALLY IN REFERENCE TO WHAT YOU WROTE!

    Or, don't you know how an OS works?
     
    Neil Gould, Jul 23, 2012
    #16
  17. Soundhaspriority

    Alan Browne Guest

    "an external hard drive". That's a weak backup strategy no matter where
    the physical location is.
    I certainly did. But I guess you can't read. The point is that the 5
    year warranty does absolutely nothing to protect your data. In my case
    data represents many thousands of hours of work. Dependence on hard
    disks (or any storage) is not part of the plan.

    The warranty on the drive is not worth 1 hour of my time. The cost of a
    2 TB hard disk is not worth 1 hour of my time.

    That you're fooled into thinking that a 5 year warranty is some
    indication of quality or that these drives will last longer than a drive
    announced with 1 yr warranty just indicates your general innocence.

    A 5 year warranty is in fact an accounting provision. They charge a
    higher price and allocate the cash to the warranty pool. As drives are
    shipped to replace failed drives, the warranty pool money is transferred
    from the warranty account to the operations account.

    Nothing in that protects your data of course. So just abandon all hope
    that warranties mean endurance.
    Goodby troll.
     
    Alan Browne, Jul 23, 2012
    #17
  18. Soundhaspriority

    Scott Dorsey Guest

    Neil, he's saying that he's using it in a read-only (or read-mostly)
    application, so it doesn't matter what the OS does.

    This is really the perfect application for the things.
    --scott
     
    Scott Dorsey, Jul 23, 2012
    #18
  19. Soundhaspriority

    Neil Gould Guest

    It very much matters what the OS does, unless one can significantly
    reconfigure the OS or use an OS that doesn't depend on virtual memory. To my
    understanding, neither has been made easier with more recent OSs.
     
    Neil Gould, Jul 23, 2012
    #19
  20. Soundhaspriority

    Scott Dorsey Guest

    No, he's not paging or swapping to the flash drive. That is instant death.
    --scott
     
    Scott Dorsey, Jul 23, 2012
    #20
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