Did they change the booting option for SL?

Discussion in 'macOS' started by Gloor, Feb 23, 2010.

  1. Gloor macrumors 6502a

    Apr 19, 2007

    I was wondering if Apple changed the way that we can set the default option for our SL system. As most of my application are 64bit it would be nice to change the default to 64bit without holding the 6 and 4 whilst rebooting.
    So, has Apple changed it or do we still need to do it manually each time we boot up?

    Thanks in advance
  2. spinnerlys Guest


    Sep 7, 2008
    forlod bygningen
    No, Apple has not changed the booting process to use the 64-bit kernel.

    But you can use your 64-bit applications even if you booted into the 32-bit kernel.

    I do that right now. Have a look at Activity Monitor and see for yourself.

  3. maflynn Moderator


    Staff Member

    May 3, 2009
    You're confusing booting into the 64bit kernel and running 64bit apps.

    By default SL will boot up the 32bit kernel but even with the 32bit kernel the OS is still capable of running 64bit programs.
  4. Gloor thread starter macrumors 6502a

    Apr 19, 2007
    I know that it can run it but presumably if you want to run native 64bit then you should also have kernel in 64bit too, correct? That way you only get the real benefits of the whole 64bit, correct? I remember reading it ages ago but forgot the details so I hope I'm not confused again :)
  5. velocityg4 macrumors 601


    Dec 19, 2004
    You could just edit the kernel flags in the com.boot.apple.plist file to default to 64bit. The article does not mention it but to actually edit, save and successfully use the changes you will need to do the following.

    Option 1:
    1. Enable root
    2. Make the edit
    3. reboot

    Option 2:
    1. copy the file to the desktop
    2. edit the file
    3. copy it back to the location
    4. open Terminal
    5. In Terminal you will need to input the following entries* (you can copy and paste the commands)

    sudo chown -R root:wheel /Library/Preferences/SystemConfiguration/com.apple.boot.plist

    sudo chmod -R 755 /Library/Preferences/SystemConfiguration/com.apple.Boot.plist

    6. For good measure open Disk Utility and repair permissions.
    7. reboot.

    The reason for either of these procedures is that the file being edited is a System file. By enabling and logging in a root you are the System and have privileges to edit system files. With option 2 since you are not the System, you must edit the file in a non System folder. After placing the file back in a System folder you have to run the above Terminal commands to change the ownership of the file back to the System. Otherwise the System will ignore the file it has no privileges to and create a new default com.apple.boot.plist file.

    *Note: As I recall, to input these entries your administrator account must have a password. Terminal will not accept a blank password.
  6. Gloor thread starter macrumors 6502a

    Apr 19, 2007
  7. Norskman macrumors member


    Feb 23, 2010
    Does it make sense to modify this so I'm booting into a true 64-bit environment?

    I'm guessing there's a reason it's not doing this by default?
  8. Nihilvor macrumors member

    Jan 25, 2010
    Because some applications don't work with the 64 bit kernal enabled. However, the only thing I've ever found that doesn't work on my machine is the Symantec live update program (though Norton Virus Checker works find itself, if I ever feel like running it).

    I'm running a lot, with no problems with the 64bit kernal, and if I have a problem, I'd hold down the "3" and "2" key on a boot (I have it defaulting to 64 bit kernal).

    There is a real speed difference between 32 bit and 64 bit kernal (although not an overwhelming difference), which can be seen if you run Geekbench. I only have the shareware 32 bit version of the program, but I always get better scores with the 64bit kernal enabled.

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