"Low-level" format in Canon A590 - what does it do?

Discussion in 'Digital Photography' started by Peabody, Feb 27, 2010.

  1. Peabody

    Peabody Guest

    Does anyone happen to know what exactly happens in the "low-level"
    format of an SD card in a Canon P&S? What I'm specifically trying
    to find out is whether it erases the card before intializing the
    file system. In flash memory, erasing is not just overwriting, but
    actually returning the memory to its unprogrammed state, like what
    we used to do with UV light applied to an EPROM.

    I'm trying to get the maximum video write speed for another
    application, and in theory an erased card will write faster. I
    can't find any other way to erase a card, so I thought maybe the
    Canon would do it.
    Peabody, Feb 27, 2010
    #1
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  2. On 2/27/2010 12:02 PM, Peabody wrote:
    > Does anyone happen to know what exactly happens in the "low-level"
    > format of an SD card in a Canon P&S? What I'm specifically trying
    > to find out is whether it erases the card before intializing the
    > file system. In flash memory, erasing is not just overwriting, but
    > actually returning the memory to its unprogrammed state, like what
    > we used to do with UV light applied to an EPROM.
    >
    > I'm trying to get the maximum video write speed for another
    > application, and in theory an erased card will write faster. I
    > can't find any other way to erase a card, so I thought maybe the
    > Canon would do it.
    >
    >
    >
    >

    My first suggestion is to try it and see what happens. I will not hurt
    the card. I've heard that it's not a good idea to format a card outside
    of the camera so do it in the camera for safety. I don't think that it
    will make much difference but it can't hurt to try. If you really want
    to do this right get a card with 6 speed rating. In the case of video
    the sustained wright speed is more important than the much more
    advertised burst rate. You can find this rating on the SD card unclosed
    in braces like this (6). a much slower 2 or 4 speed are much more common.

    John Passaneau
    John Passaneau, Feb 27, 2010
    #2
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  3. Peabody

    Ray Fischer Guest

    Peabody <> wrote:
    >Does anyone happen to know what exactly happens in the "low-level"
    >format of an SD card in a Canon P&S? What I'm specifically trying
    >to find out is whether it erases the card before intializing the
    >file system.


    How long does it take?

    Completely erasing a 2GB memory card should take a minute or two.
    Writing a new file system will take a couple of seconds.

    > In flash memory, erasing is not just overwriting, but
    >actually returning the memory to its unprogrammed state, like what
    >we used to do with UV light applied to an EPROM.


    Nobody does that. It's probably not possible.

    >I'm trying to get the maximum video write speed for another
    >application, and in theory an erased card will write faster. I
    >can't find any other way to erase a card, so I thought maybe the
    >Canon would do it.


    You'd do better to get a faster memory card and stop wasting time on
    chasing a mythical 1% speed increase.

    --
    Ray Fischer
    Ray Fischer, Feb 27, 2010
    #3
  4. Peabody

    ray Guest

    On Sat, 27 Feb 2010 11:02:35 -0600, Peabody wrote:

    > Does anyone happen to know what exactly happens in the "low-level"
    > format of an SD card in a Canon P&S? What I'm specifically trying to
    > find out is whether it erases the card before intializing the file
    > system. In flash memory, erasing is not just overwriting, but actually
    > returning the memory to its unprogrammed state, like what we used to do
    > with UV light applied to an EPROM.
    >
    > I'm trying to get the maximum video write speed for another application,
    > and in theory an erased card will write faster. I can't find any other
    > way to erase a card, so I thought maybe the Canon would do it.


    I can't speak to that particular camera, but I can tell you a few
    generalities gathered from 30 years as a computer professional:

    1) it is probably best to format a card in the camera you intend to use
    it on. Reason: some cameras have an incomplete implementation of the
    filesystem structure (due to the fact that they contain very limited
    processing power). That is the main reason that they sometimes become
    corrupted after a bit of saving and deleting images. That problem is not
    as bad as it used to be, but . . .

    2) you should be able to do a low level format in a card reader attached
    to a computer. If you did that, I'd still recommend doing a 'quick
    format' on the camera it will be used with. Fact is, they are not using
    any novel filesystem on the cards - they are still a variant of MS
    filesystems - so most computers should understand that.

    3) the main advantage of a 'low level' format on a memory card would be
    that the data is erased - overwritten. A 'quick format' simply resets the
    file allocation table - removing the directory contents. Until some data
    is overwritten, the previous data can still be retrieved with varying
    degrees of success.

    I'd be surprised if the access was measurably faster on a low level
    formatted card than one that had a quick format done. To my knowledge, it
    does not make in difference in write time depending on what was there
    before, but I could be wrong on that point.
    ray, Feb 27, 2010
    #4
  5. Peabody

    Ted Banks Guest

    On Sat, 27 Feb 2010 11:02:35 -0600, Peabody <>
    wrote:

    >Does anyone happen to know what exactly happens in the "low-level"
    >format of an SD card in a Canon P&S? What I'm specifically trying
    >to find out is whether it erases the card before intializing the
    >file system. In flash memory, erasing is not just overwriting, but
    >actually returning the memory to its unprogrammed state, like what
    >we used to do with UV light applied to an EPROM.
    >
    >I'm trying to get the maximum video write speed for another
    >application, and in theory an erased card will write faster. I
    >can't find any other way to erase a card, so I thought maybe the
    >Canon would do it.
    >
    >
    >


    For the speed issue:

    If it's an SD card and not an SDHC card (4GB or less only, though some 4GB
    cards are also SDHC) format it in FAT16. It can improve the write speed up
    to 30% in Canon P&S cameras. Don't use the camera, use your computer and a
    card-reader for this. Formatting in the camera will format it as FAT32.

    After using it for a while for many files and file deletions and it seems
    to slow down, you can retain that speed by using Windows tools to
    defragment it. It will speed up as if freshly formatted in FAT16 again
    without a reformat needed. Most other stand-alone defragment utilities
    don't seem to recognize SD cards in a card reader. Contrary to most of the
    opinions you'll read online by those who post what they don't really know,
    defragmenting does work as well as a fresh format. Defragment twice, as one
    time doesn't seem to catch all of the gaps the first time.
    Ted Banks, Feb 27, 2010
    #5
  6. Peabody

    Ted Banks Guest

    On 27 Feb 2010 18:52:49 GMT, (Ray Fischer) wrote:

    >Peabody <> wrote:
    >>Does anyone happen to know what exactly happens in the "low-level"
    >>format of an SD card in a Canon P&S? What I'm specifically trying
    >>to find out is whether it erases the card before intializing the
    >>file system.

    >
    >How long does it take?
    >
    >Completely erasing a 2GB memory card should take a minute or two.
    >Writing a new file system will take a couple of seconds.
    >
    >> In flash memory, erasing is not just overwriting, but
    >>actually returning the memory to its unprogrammed state, like what
    >>we used to do with UV light applied to an EPROM.

    >
    >Nobody does that. It's probably not possible.
    >
    >>I'm trying to get the maximum video write speed for another
    >>application, and in theory an erased card will write faster. I
    >>can't find any other way to erase a card, so I thought maybe the
    >>Canon would do it.

    >
    >You'd do better to get a faster memory card and stop wasting time on
    >chasing a mythical 1% speed increase.


    Contrary to that opinion, class ratings for cards are for read-speed only.
    The write speed can be as low as 50% of that, so using tricks like
    formatting in FAT16 can be more beneficial for write-speed than just buying
    a faster card and wasting your money for no appreciable write-speed gain.
    Ted Banks, Feb 27, 2010
    #6
  7. Ted Banks wrote:
    > On Sat, 27 Feb 2010 11:02:35 -0600, Peabody <>
    > wrote:
    >
    >> Does anyone happen to know what exactly happens in the "low-level"
    >> format of an SD card in a Canon P&S? What I'm specifically trying
    >> to find out is whether it erases the card before intializing the
    >> file system. In flash memory, erasing is not just overwriting, but
    >> actually returning the memory to its unprogrammed state, like what
    >> we used to do with UV light applied to an EPROM.
    >>
    >> I'm trying to get the maximum video write speed for another
    >> application, and in theory an erased card will write faster. I
    >> can't find any other way to erase a card, so I thought maybe the
    >> Canon would do it.


    > For the speed issue:
    >
    > If it's an SD card and not an SDHC card (4GB or less only, though some 4GB
    > cards are also SDHC) format it in FAT16. It can improve the write speed up
    > to 30% in Canon P&S cameras. Don't use the camera, use your computer and a
    > card-reader for this. Formatting in the camera will format it as FAT32.
    >
    > After using it for a while for many files and file deletions and it seems
    > to slow down, you can retain that speed by using Windows tools to
    > defragment it. It will speed up as if freshly formatted in FAT16 again
    > without a reformat needed. Most other stand-alone defragment utilities
    > don't seem to recognize SD cards in a card reader. Contrary to most of the
    > opinions you'll read online by those who post what they don't really know,
    > defragmenting does work as well as a fresh format. Defragment twice, as one
    > time doesn't seem to catch all of the gaps the first time.
    >


    Simply reformat it once in camera. Done.

    --
    John McWilliams
    John McWilliams, Feb 28, 2010
    #7
  8. Peabody

    LOL! Guest

    On Sat, 27 Feb 2010 18:55:57 -0800, John McWilliams <>
    wrote:

    >Ted Banks wrote:
    >> On Sat, 27 Feb 2010 11:02:35 -0600, Peabody <>
    >> wrote:
    >>
    >>> Does anyone happen to know what exactly happens in the "low-level"
    >>> format of an SD card in a Canon P&S? What I'm specifically trying
    >>> to find out is whether it erases the card before intializing the
    >>> file system. In flash memory, erasing is not just overwriting, but
    >>> actually returning the memory to its unprogrammed state, like what
    >>> we used to do with UV light applied to an EPROM.
    >>>
    >>> I'm trying to get the maximum video write speed for another
    >>> application, and in theory an erased card will write faster. I
    >>> can't find any other way to erase a card, so I thought maybe the
    >>> Canon would do it.

    >
    >> For the speed issue:
    >>
    >> If it's an SD card and not an SDHC card (4GB or less only, though some 4GB
    >> cards are also SDHC) format it in FAT16. It can improve the write speed up
    >> to 30% in Canon P&S cameras. Don't use the camera, use your computer and a
    >> card-reader for this. Formatting in the camera will format it as FAT32.
    >>
    >> After using it for a while for many files and file deletions and it seems
    >> to slow down, you can retain that speed by using Windows tools to
    >> defragment it. It will speed up as if freshly formatted in FAT16 again
    >> without a reformat needed. Most other stand-alone defragment utilities
    >> don't seem to recognize SD cards in a card reader. Contrary to most of the
    >> opinions you'll read online by those who post what they don't really know,
    >> defragmenting does work as well as a fresh format. Defragment twice, as one
    >> time doesn't seem to catch all of the gaps the first time.
    >>

    >
    >Simply reformat it once in camera. Done.


    You're a moron.
    LOL!, Feb 28, 2010
    #8
  9. LOL! wrote:
    > On Sat, 27 Feb 2010 18:55:57 -0800, John McWilliams <>
    > wrote:
    >
    >> Ted Banks wrote:
    >>> On Sat, 27 Feb 2010 11:02:35 -0600, Peabody <>
    >>> wrote:
    >>>
    >>>> Does anyone happen to know what exactly happens in the "low-level"
    >>>> format of an SD card in a Canon P&S? What I'm specifically trying
    >>>> to find out is whether it erases the card before intializing the
    >>>> file system. In flash memory, erasing is not just overwriting, but
    >>>> actually returning the memory to its unprogrammed state, like what
    >>>> we used to do with UV light applied to an EPROM.
    >>>>
    >>>> I'm trying to get the maximum video write speed for another
    >>>> application, and in theory an erased card will write faster. I
    >>>> can't find any other way to erase a card, so I thought maybe the
    >>>> Canon would do it.
    >>> For the speed issue:
    >>>
    >>> If it's an SD card and not an SDHC card (4GB or less only, though some 4GB
    >>> cards are also SDHC) format it in FAT16. It can improve the write speed up
    >>> to 30% in Canon P&S cameras. Don't use the camera, use your computer and a
    >>> card-reader for this. Formatting in the camera will format it as FAT32.
    >>>
    >>> After using it for a while for many files and file deletions and it seems
    >>> to slow down, you can retain that speed by using Windows tools to
    >>> defragment it. It will speed up as if freshly formatted in FAT16 again
    >>> without a reformat needed. Most other stand-alone defragment utilities
    >>> don't seem to recognize SD cards in a card reader. Contrary to most of the
    >>> opinions you'll read online by those who post what they don't really know,
    >>> defragmenting does work as well as a fresh format. Defragment twice, as one
    >>> time doesn't seem to catch all of the gaps the first time.
    >>>

    >> Simply reformat it once in camera. Done.

    >
    > You're a moron.



    Right, "Ted".... always take the more convoluted path.

    --
    lsmft
    John McWilliams, Feb 28, 2010
    #9
  10. Peabody

    LOL! Guest

    On Sat, 27 Feb 2010 20:24:54 -0800, John McWilliams <>
    wrote:

    >LOL! wrote:
    >> On Sat, 27 Feb 2010 18:55:57 -0800, John McWilliams <>
    >> wrote:
    >>
    >>> Ted Banks wrote:
    >>>> On Sat, 27 Feb 2010 11:02:35 -0600, Peabody <>
    >>>> wrote:
    >>>>
    >>>>> Does anyone happen to know what exactly happens in the "low-level"
    >>>>> format of an SD card in a Canon P&S? What I'm specifically trying
    >>>>> to find out is whether it erases the card before intializing the
    >>>>> file system. In flash memory, erasing is not just overwriting, but
    >>>>> actually returning the memory to its unprogrammed state, like what
    >>>>> we used to do with UV light applied to an EPROM.
    >>>>>
    >>>>> I'm trying to get the maximum video write speed for another
    >>>>> application, and in theory an erased card will write faster. I
    >>>>> can't find any other way to erase a card, so I thought maybe the
    >>>>> Canon would do it.
    >>>> For the speed issue:
    >>>>
    >>>> If it's an SD card and not an SDHC card (4GB or less only, though some 4GB
    >>>> cards are also SDHC) format it in FAT16. It can improve the write speed up
    >>>> to 30% in Canon P&S cameras. Don't use the camera, use your computer and a
    >>>> card-reader for this. Formatting in the camera will format it as FAT32.
    >>>>
    >>>> After using it for a while for many files and file deletions and it seems
    >>>> to slow down, you can retain that speed by using Windows tools to
    >>>> defragment it. It will speed up as if freshly formatted in FAT16 again
    >>>> without a reformat needed. Most other stand-alone defragment utilities
    >>>> don't seem to recognize SD cards in a card reader. Contrary to most of the
    >>>> opinions you'll read online by those who post what they don't really know,
    >>>> defragmenting does work as well as a fresh format. Defragment twice, as one
    >>>> time doesn't seem to catch all of the gaps the first time.
    >>>>
    >>> Simply reformat it once in camera. Done.

    >>
    >> You're a moron.

    >
    >
    >Right, "Ted".... always take the more convoluted path.


    http://chdk.wikia.com/wiki/Benchmarks

    You're a moron.

    You weren't just happy with being told that you are a moron, you insisted
    that I prove you are a moron to the whole world.

    Better to remain silent and be thought a fool than to open your mouth again
    and remove all doubt again.


    LOL!
    LOL!, Feb 28, 2010
    #10
  11. Peabody

    dwight Guest

    "Peabody" <> wrote in message
    news:...
    > Does anyone happen to know what exactly happens in the "low-level"
    > format of an SD card in a Canon P&S? What I'm specifically trying
    > to find out is whether it erases the card before intializing the
    > file system. In flash memory, erasing is not just overwriting, but
    > actually returning the memory to its unprogrammed state, like what
    > we used to do with UV light applied to an EPROM.
    >
    > I'm trying to get the maximum video write speed for another
    > application, and in theory an erased card will write faster. I
    > can't find any other way to erase a card, so I thought maybe the
    > Canon would do it.
    >


    It's a good question, and one that I've wondered about, myself. My S3 has
    the low level format option, but the manual only has this to say:

    "You should select the [Low Level Format] option if you suspect the
    read/write speed of a memory card has dropped. A low level format may
    require 2 to 3 minutes with some memory cards."

    Not big on specifics.

    dwight
    dwight, Feb 28, 2010
    #11
  12. LOL! wrote:

    > Better to remain silent and be thought a fool than to open your mouth again
    > and remove all doubt again.


    Yes, lol, Ted, and a dozen other nyms per month, words which may haunt......

    --
    lsmft

    Remember: Opinions are like buttocks; only those which are well-formed
    should be shown in public.
    John McWilliams, Feb 28, 2010
    #12
  13. Peabody

    whisky-dave Guest

    "Peabody" <> wrote in message
    news:...
    > Does anyone happen to know what exactly happens in the "low-level"
    > format of an SD card in a Canon P&S? What I'm specifically trying
    > to find out is whether it erases the card before intializing the
    > file system. In flash memory, erasing is not just overwriting, but
    > actually returning the memory to its unprogrammed state, like what
    > we used to do with UV light applied to an EPROM.
    >
    > I'm trying to get the maximum video write speed for another
    > application, and in theory an erased card will write faster.


    What do you mean by another aplpication.
    I find that erasing/reformating a card to the Mac OS journaled copies files
    faster
    than using FAT32 formatede card on my iMac.

    Another thing I've noticed that DVD +R can be written to faster than DVD -R
    when used in my Sony DVD recorder

    > I
    > can't find any other way to erase a card, so I thought maybe the
    > Canon would do it.


    If you're using a computer there are a few ways of erasing depending on the
    OS
    you use.

    >
    >
    >
    >
    whisky-dave, Mar 4, 2010
    #13
  14. Peabody

    Peabody Guest

    whisky-dave says...

    >> Does anyone happen to know what exactly happens in the
    >> "low-level" format of an SD card in a Canon P&S? What
    >> I'm specifically trying to find out is whether it
    >> erases the card before intializing the file system. In
    >> flash memory, erasing is not just overwriting, but
    >> actually returning the memory to its unprogrammed
    >> state, like what we used to do with UV light applied to
    >> an EPROM.


    >> I'm trying to get the maximum video write speed for
    >> another application, and in theory an erased card will
    >> write faster.


    > What do you mean by another aplpication. I find that
    > erasing/reformating a card to the Mac OS journaled
    > copies files faster than using FAT32 formatede card on
    > my iMac.


    The other application is just another camera - a very cheap
    one with not a lot of computing power. It records
    motion-JPEG video, 720x480P, 30 fps, along with PCM
    16-bit mono audio sampled at 22K. The average write speed
    to the card is about 1.3 megabytes per second, and the
    camera appears to have some trouble keeping up.

    So I've gone to a class 6 card, which seems to help, but
    just wanted to give it the benefit of anything I can do to
    make sure writing to the card isn't slowing things down.

    My understanding is that flash memory only writes in one
    direction, meaning that you can change a 1 to a 0 by
    overwriting, but not a 0 to a 1. So, once a new card has
    been filled up once, every subsequent write has to be
    preceeded by an "erase", which resets everything back to all
    1's. The card's internal controller does this
    automatically, but it takes time. So rather than doing the
    erasing in real time, I would like to erase it ahead of
    time, and I was hoping the Canon low-level format would do
    that. I don't know of any other way to erase a card. The
    Windows format operation doesn't.

    There is a program at sdcard.org that claims to erase, but
    it tells me my "interface device" doesn't support it.

    > If you're using a computer there are a few ways of
    > erasing depending on the OS you use.


    I'm running Windows XP.
    Peabody, Mar 4, 2010
    #14
  15. Peabody

    Ray Fischer Guest

    Peabody <> wrote:
    >My understanding is that flash memory only writes in one
    >direction, meaning that you can change a 1 to a 0 by
    >overwriting, but not a 0 to a 1. So, once a new card has
    >been filled up once, every subsequent write has to be
    >preceeded by an "erase", which resets everything back to all
    >1's. The card's internal controller does this
    >automatically, but it takes time. So rather than doing the
    >erasing in real time, I would like to erase it ahead of
    >time, and I was hoping the Canon low-level format would do
    >that.


    Your theory makes an assumption which is unlikely to be true: That the
    "controller" first reads a block in order to determine whether it
    needs to do one of these double writes.

    --
    Ray Fischer
    Ray Fischer, Mar 4, 2010
    #15
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