Chose 150gb partition, bootcamp shows 161gb why?

Discussion in 'Windows, Linux & Others on the Mac' started by ozreth, May 8, 2010.

  1. ozreth macrumors 65816

    ozreth

    Joined:
    Nov 5, 2009
    #1
    Just made my bootcamp partition and chose 150gb. Installed Windows 7 and booted back into OSX. Shows 161.53gb on the Windows drive.

    What happened?
     
  2. DoFoT9 macrumors P6

    DoFoT9

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    #2
    hmm probably something to do with variances in how each OS classifies bits v bytes
     
  3. Bengt77 macrumors 68000

    Bengt77

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    #3
    Apple changed the way the OS reports drive size quantities. In Snow Leopard, 1000 bytes is 1 kilobyte (KB), like it should be. Before Snow Leopard, 1024 bytes was faultily being reported as being 1 kilobyte, while it actually was 1 kibibyte (KiB). Windows (any version) still reports drive sizes that way. In essence, Apple went from binary to decimal values (Wikipedia article).

    Here's how that works:

    161,53GiB = 161.530.000.000 bytes > 161.530.000.000 / 1024^3 ≈ 150GB

    On the other hand, if you create a 150GB partition in Snow Leopard, that volume will be reported as being only 139,7GB in Windows (although what Windows calls GB is actually GiB). If that's what you actually did and Boot Volume said the partition would be 150GB, that means the application knows how Windows handles things. It means it does the conversion for you. If all this in indeed the case, Boot Camp probably does all that to prevent you from thinking, when using Windows and checking your partition size, that 11,53GB was magically vaporized from your partition.

    EDIT: Does all this make any sense? Did it answer your question?
     
  4. DoFoT9 macrumors P6

    DoFoT9

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    #4
    love it ben ;) thats a lot of effort you went through! lol
     
  5. ozreth thread starter macrumors 65816

    ozreth

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    Nov 5, 2009
    #5
    Hahaha yeah it made enough sense, and thank you : )

    Unfortunately I am a freak and will have to probably repartition as 139gb so that I can have it read 150.
     
  6. Bengt77 macrumors 68000

    Bengt77

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    #6
    Thanks, guys. I still had it skewed, though. I had the units mixed up. The actual calculation should be this:

    161,53GB = 161.530.000.000 bytes > 161.530.000.000 / 1024^3 ≈ 150GiB

    Man, you sure are hard on yourself! :D
     
  7. GroundLoop macrumors 68000

    GroundLoop

    Joined:
    Mar 21, 2003
    #7
    Umm...I think you have that backwards...

    150GiB = (roughly) 161 GB since 1GiB = (roughly) 1.074GB

    So for the OPs situation to occur, the tool used to partition the hard drive must have been using GiB and the Windows OS used GB.

    Hickman

    Edit: just noticed he said he was back in OSX which does use GB (not GiB). So I guess this means that the BootCamp partition tool still uses GiB. I can see why people would be confused since this tool is supplied by Apple and should conform to their drive size reporting standards.
     
  8. Bengt77 macrumors 68000

    Bengt77

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    #8
    Yeah, you're right. I corrected myself in a later post, though. But thanks for the heads up!
     
  9. ozreth thread starter macrumors 65816

    ozreth

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    #9
    Im back! Is there an easy way to change a partition amount?
     
  10. DoFoT9 macrumors P6

    DoFoT9

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    #10
    OSX disk utility can do it, but generally it will delete all contents off of that partition
     
  11. balamw Moderator

    balamw

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    #11
  12. ozreth thread starter macrumors 65816

    ozreth

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    #12

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