Snow Leopard arrived yesterday right when Apple said it would be delivered.

I ran the install on my iMac this morning. I can’t rightly say how long it took because I went off and did other things while it worked away.

However, it installed without a hitch.

By default it runs in 32-bit mode for compatibility reasons. You can check this by doing a

uname -a

in a terminal window.

You can also use System Profiler and check the “64-bit Kernel and Extensions” under “Software” if you’re a clickety-click type person.

I will have a little issue getting 64-bit working on my Macbook 2,1. While the processor supports it fine, the Firmware has limited it to 32-bit. I hear there are work-arounds for this and will need to investigate. To check if your firmware supports 64-bit mode run the following command in a terminal window:

ioreg -l -p IODeviceTree | grep firmware-abi

Check the EFI result, 64 is what you’re wanting to see.

To boot your new install into 64-bit mode, simply hold down the 6 and 4 keys while the computer boots. Reboot to go back to 32-bit mode.

To make the 64-bit switch permanent edit the file:
/Library/Preferences/SystemConfiguration/com.apple.Boot.plist

find:
Kernel Flags


change to:
Kernel Flags
arch=x86_64

and reboot.

If you then wish to duck back into 32-bit mode just hold down the 3 and 2 keys while the system is booting.

Tags: OS X, apple