Hard drive space not adding up. Help?

Discussion in 'macOS' started by krazy karl, Jan 4, 2007.

  1. krazy karl macrumors newbie

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    Jan 4, 2007
    #1
    I recently purchased a 17" C2D MacBook Pro with 2GB RAM and the 160GB HD. I noticed that I did not have as much free space as I thought I did so I went investigating. This lead me to downloading WhatSize and running it. It, as well as OSX tells me that I am using about 97 GB, but when I add up the size of the folders and files on my HD in WhatSize, I find that I am only using about 53 GB, if that. Why might this be? Seems curious to me.
     
  2. WildCowboy Administrator/Editor

    WildCowboy

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    Jan 20, 2005
    #2
    Are you running WhatSize from an account with administrator privileges? If not, it won't be able to see things in other accounts or the System folders/files I believe.
     
  3. mischief macrumors 68030

    mischief

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    Aug 1, 2001
    Location:
    Santa Cruz Ca
    #3
    Evidently you have a LOT of invisible files. When was the last time you emptied your trash? Does your Spotlight icon pulse a lot? Have you ever run the CRON scripts?
     
  4. monke macrumors 65816

    monke

    Joined:
    May 30, 2005
    #4
    I have the same problem too, except with my MyBook. I just got the 320Gb and it shows that there are only 297.33 Gb free, with 700 Mb being used.

    Thoughts? :)
     
  5. mischief macrumors 68030

    mischief

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    Location:
    Santa Cruz Ca
    #5
    Good point.
     
  6. krazy karl thread starter macrumors newbie

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    Jan 4, 2007
    #6
    Yes, I have administrator privileges, I am the only account on the computer too.

    Trash is empty, I have been emptying it freqently as I am moving a bunch of data around. Spotlight icon doesn't seem to pulse, and what are the CRON scripts?
     
  7. WildCowboy Administrator/Editor

    WildCowboy

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    #7
    That's completely correct due to the gigabyte/gibibyte confusion. Your computer sees a 320 GB drive as a 297 GB drive because it uses the wrong units.
     
  8. psychofreak Retired

    psychofreak

    Joined:
    May 16, 2006
    Location:
    London
    #8
    I hate the system. Stick it to the man!
    Hopefully with all these waste of space posts I'll get a better status soon, haha!
     
  9. uaaerospace macrumors 6502

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    Feb 15, 2005
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    Alabama
    #9
    How much swap space is being used when you are running that check? I bet that's a big chunk.
     
  10. monke macrumors 65816

    monke

    Joined:
    May 30, 2005
    #10
    OK, I don't get it all that much, but w/e. I'll just agree with psychofreak. :)
     
  11. krazy karl thread starter macrumors newbie

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    Jan 4, 2007
    #11
    Swap space, how do i find that out?
     
  12. uaaerospace macrumors 6502

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    Feb 15, 2005
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    Alabama
    #12
    You can estimate by opening Activity Monitor. In the process listing, look at the Virtual Memory column. Go get your calculator ;)

    EDIT: haha, scratch that. Just click on the System Memory option in Activity Monitor. It tells you the VM size.
     
  13. WildCowboy Administrator/Editor

    WildCowboy

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    #13
    It comes from the fact that a gigabyte should be equal to a 1000 megabytes. This is how hard drive manufacturers advertise their products, and this is how they should do it.

    But computers prefer to think in powers of two, so they say that a gigabyte is 1024 megabytes. Technically, this is incorrect, and a whole other system of nomenclature in which the term "gibibyte" is the near-equivalent of "gigabyte" should be used. But the insistence of computers on using the incorrect "gigabyte" term causes a discrepancy of 2.4% between the two systems of measurement. Unfortunately, this discrepancy is compounded for each 1000-fold increase in number (bytes --> kilobytes --> megabytes --> gigabytes). Now that gigabytes are standard capacities for hard drives, the discrepancy has reached about 7%, which makes it seem like your hard drive has a lot of missing space.

    But I'm not sure which is more confusing to consumers...having to explain this difference or having to explain to them what a gibibyte is.
     
  14. Canerican macrumors regular

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    Jul 22, 2006
    #14
    And try explaining a bit is a 1 or a 0... and this is all that makes the computer run...:eek:
     
  15. krazy karl thread starter macrumors newbie

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    Jan 4, 2007
    #15
    VM size is just over 15 GB, that still puts me 25+ GB uncalled for.
     
  16. Canerican macrumors regular

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    Jul 22, 2006
    #16
    Also a 160GB HDD will only be about 150-155GB... chalk that down to 15-20GB.
     
  17. monke macrumors 65816

    monke

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    May 30, 2005
    #17
    Ahhh! Thanks for that. :)

    Don't even go there. :p :D
     
  18. WildCowboy Administrator/Editor

    WildCowboy

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    #18
    Just as a frame of reference, here are my stats on a PowerBook with one user account and a 100 GB hard drive that ends up at 93.0 GB because of the aforementioned gibigyte issue.

    WhatSize says that I have 49.8 GB used, and 43.2 GB available...check.

    Adding up all of the individual folders/files WhatSize sees gives me 48.4 MB, so I'm missing 1.4 GB there. My virtual memory, according to Activity Monitor is currently 9.30 GB.
     
  19. krazy karl thread starter macrumors newbie

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    Jan 4, 2007
    #19
    No, I have already accounted for the fact that my hard drive is only 148.73 GB. so, there is still about 25 GB missing....
     
  20. krazy karl thread starter macrumors newbie

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    Jan 4, 2007
    #20
    wild cowboy, if you add up the size of the files and folders on your HD in WhatSize do they add up correctly because mine don't.
     
  21. WildCowboy Administrator/Editor

    WildCowboy

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    #21
    As I mentioned a couple of posts up, adding them up comes up about 1.4 GB short. I don't really know what's causing the discrepancy, but mine's not nearly as big as yours seems to be.
     
  22. krazy karl thread starter macrumors newbie

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    Jan 4, 2007
    #22
    oops, read that and then spaced. I am new to macs so i'm not sure if this applies to them too, but are there hidden files that could be floating around somewhere?
     
  23. WildCowboy Administrator/Editor

    WildCowboy

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    #23
    Yes, there are hidden, invisible files, but WhatSize can see those if you are an administrator on the computer. I'm stumped...I just don't have enough experience in this area to figure it out.
     
  24. bankshot macrumors 65816

    bankshot

    Joined:
    Jan 23, 2003
    Location:
    Southern California
    #24
    VM size will not tell you how much disk space is actually used for swap. VM size simply tells you how much memory all the various programs have told OS X to reserve for them, just in case they need it. In general, much of this is never used.

    To find the actual disk space used by swap, you need to look in /var/vm. You may need administrator or superuser privileges to do so. To do it from Terminal, run this command:
    Code:
    sudo du -hs /var/vm
    From the Finder, you can use Cmd-Shift-G and type in /var/vm to get there.

    To illustrate this, here are the VM sizes and actual swap space used (in /var/vm) on some of my machines:

    1. VM size 12.9G, swap 2.2G
    2. VM size 8.8G, swap 1.0G
    3. VM size 4.9G, swap 0.5G


    As for the original question, WhatSize is not an effective tool for measuring total disk space usage. It does not appear to tell you when it encounters directories that your user does not have permission to go into. Instead, it silently skips them.

    On a system with multiple user accounts, the bulk of the discrepancy will likely be in areas of other accounts that your user does not have permission to view (it doesn't matter if you're an administrator - that's not the same level as superuser). Do a little experiment in the Terminal. First run this command:
    Code:
    du -hsx /Users
    The number you get should agree with what you got from WhatSize, within some roundoff differences. Notice any messages about "permission denied". Then, do this command, which runs the same thing as superuser (it will ask you for your own password - you must be at least an administrator user at this point):
    Code:
    sudo du -hsx /Users
    You'll probably get a higher number.

    In fact, you can do the same thing that WhatSize does, only better, from the Terminal. To get true sizes of all folders in the root directory, simply do this:
    Code:
    sudo du -hsx /* /.??*
    Another major strike against WhatFile is that it appears to invent file space usage out of thin air. My Developer folder has subfolders with sizes 734M, 186M, 72M, 62M, 1.2M, 1.6M, 1.1M, 1.8M, 0.5M, 0.4M, and 0.16M. WhatSize tells me that adds up to 1.36G. You do the math. I wouldn't trust this app for anything.
     

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