Disk size ?

Discussion in 'MacBook Air' started by komoornik, Oct 29, 2011.

  1. komoornik macrumors regular

    Joined:
    Jul 29, 2011
    #1
    I've installed Win 7 via Bootcamp. Divided SSD - Mac OS X told be it would be 23 GB for it and over 97 GB for Bootcamp ( which would be ~120 GB, that's fine for a 128GB SSD ).

    But i don't why Windows 7 says the Bootcamp partition got 90,7 GB and Mac OS X got 21,4 GB ?
     
  2. simsaladimbamba

    Joined:
    Nov 28, 2010
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    #2
    Mac OS X uses base 10 figures to show file sizes, meaning 128 billion bytes are shown as 128GB, while Windows still uses the base 2 system, thus 128 billion bytes divided by 1024^3 is 119.2GB.
     
  3. komoornik thread starter macrumors regular

    Joined:
    Jul 29, 2011
    #3
    I think you don't understand.

    Mac OS X shows me the four partitions:
    200 MB efi, 650 MB recovery, 97 GB Bootcamp and 23 GB OS X

    It says SSD size is ~121 GB, which I know would be correct for a "128 GB" drive.

    On windows:
    90.78 GB ( bootcamp ) + 21,42 GB ( Mac OS X ) + 200 MB ( efi ) + 620 MB ( recovery ) and that's about 113 GB.

    So I'm missing more then 6 GB ?
     
  4. simsaladimbamba

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    #4
    Lets assume Mac OS X uses base 10 to show the disk size, meaning that the 121GB SSD would have 121 billion bytes to store things, but in Windows the base 2 is used to show disk and file sizes, meaning going from 1KB to 1MB uses 1024 as multiplicator instead of the 1000 Mac OS X now uses. Thus 121 billion bytes would be 112.7GB in Windows.
     
  5. komoornik thread starter macrumors regular

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    Jul 29, 2011
    #5
    So this means the actual usable size is ~121 GB ?

    So rest of the space is probably reserved by controller?
     
  6. simsaladimbamba

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    #6
    The available capacity is less than the 128GB it says it has. I have a 64GB SSD, but only 60GB is available. AFAIK the rest is used for garbage control and such shenanigans.
     

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