Files take up more space in Mac than PC?

Discussion in 'OS X Mavericks (10.9)' started by sanchopanza, Jan 22, 2014.

  1. sanchopanza macrumors newbie

    Oct 31, 2013

    Each file I transferred from PC to my new Mac via external drive takes up around 8% more space. Is it because formatting? My PC is formatted as NTFS and external drive formatted as ExFAT.
  2. MacUser2525 macrumors 68000


    Mar 17, 2007
    That would be the acceptance of the lies hard drives manufacturers tell to make you think you have larger capacity drive. Unlike your computer which runs binary the HD manufacturers list their capacity in decimal an 8% difference. So you are seeing the transferred files listed in decimal size where bigger in binary where smaller in reality they are the same size. Apple started showing the decimal display size a few years ago now if you use something like PathFinder they have preference to show your files as binary size in it.
  3. Michael Goff Suspended

    Michael Goff

    Jul 5, 2012
    It's the difference between how OS X and Windows sees a MB and a GB. I you take the same size HD, you'll notice they have different sizes depending on what OS you're using.
  4. Dark Dragoon macrumors 6502a

    Dark Dragoon

    Jul 28, 2006
    Here's the problem, giga means 1000^3 so a gigabyte can be written as 1,000,000,000 bytes which is the SI unit.
    Then there are binary units which would for a gigabyte be 1024^3 or 1,073,741,824 bytes.
    Its the same megabyte, just that the numbers are smaller.

    Gigabyte = 1,000,000,000 vs 1,073,741,824 bytes
    Megabyte = 1,000,000 vs 1,048,576 bytes
    Kilobyte = 1000 vs 1024 bytes

    So then you find out that some systems for reporting disk space, files sizes etc... use the SI unit where others use the binary unit.

    In other words the files take up the same amount of space, its just how you count it thats different.
    If you look at the size of the files in bytes they should be the same.
  5. sanchopanza thread starter macrumors newbie

    Oct 31, 2013
  6. meme1255 macrumors 6502a

    Jul 15, 2012
    Czech Republic
    Windows are counting it wrong, as since 2009 SI defines units this way:
    Si-prefix-Byte is defined as (10^3)^X , and first syllable of according SI-Prefix +bi is defined as (2^10)^X.
    =>*Kilobyte is 1000 Bytes
    Kibibyte is 1024 Bytes.

    It was changed this way to make every unit in SI use the same prefix with same meaning.
    Hard drive manufactures are using correct units. RAM should be counted in XiBs, as it's size is always power of 2. :)
  7. MacUser2525 macrumors 68000


    Mar 17, 2007
    When our computers start computing in decimal then they get to count it as decimal until then binary is it, just because they have standardized their lies means nothing.
  8. jonesea macrumors newbie

    Dec 21, 2013
    Could also be one of them is reporting spaced used on disk (in multiples of filesystem blocks) rather than actual real file size.

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