Operation under 64bit mode

[Hervé]

Hi,

 

Some time ago Ptesone had mentioned:

1) the 32/64bit kernel activation commands

'sudo systemsetup -setkernelbootarchitecture i386'

versus

'sudo systemsetup -setkernelbootarchitecture x86_64'

 

2) consequential modification of the /Library/Preferences/SystemConfiguration/com.apple.Boot.plist file

'Kernel Architecture'

'i386'

versus

'Kernel Architecture'

'x86_64'

 

 

I was wondering how that interacts or interferes with the chameleon.Boot.plist 32-bit (i386) flag? I've done a few tests to check things out and obtained different results depending on the Mac OS X versions.

 

1) D630 X3100 with Lion 10.7.4 (EDP 3 v409)

System will boot fully functional, whether the Chameleon 32-bit flag is set or not ("32-bit (i386)" check box of /Extra/org.chameleon.boot.plist when opened with Chameleon wizard).

 

Interestingly enough, the /L/P/S com.apple.Boot.plist file was found containing not only the 'Kernel Architecture' field, but also a 'Kernel Flags' field (found set at "arch=i386") and a whole set of other stuff looking like the actual Chameleon settings. What I've noticed is that, whatever the Kernel Architecture value (i386 or x86_64), the system will boot fully functional when the 'Kernel Flags' field of the file is kept to "arch=i386". However, if I changed this to "arch=x86_64", the system boots with graphics defaulting to 1024x768, no iStat, no keyboard, etc.

 

2) D620 nVidia 110M with SL 10.6.8 (EDP 3 v383)

Again, the system will boot fully functional whether the Chameleon 32-bit flag is set or not.

 

I found the /L/P/S com.apple.Boot.plist file of that system with an empty "Kernel Flags" field (i.e. empty string). In that condition:

a. if Chameleon Boot plist 32bit flag is set, the system will boot fully functional whatever the value "Kernel architecture" in L/P/S com.apple.Boot.plist file

b. if Chameleon Boot plist 32bit flag is unset, the system will not complete its boot when the value "Kernel architecture" in L/P/S com.apple.Boot.plist file is set to "arch=x86_64". System only completes its boot if the flag 'arch=i386' is manually entered at bootloader initial stage, i.e. 64bit mode does not appear viable...

 

 

Conclusion:

i. it seems that the "Kernel Flags" field of the /Library/Preferences/SystemConfiguration/com.apple.Boot.plist overwrites any Chameleon 32-bit flag setting/unsetting.

 

ii. does the "Kernel Architecture" field really serve a purpose?

 

iii. is there any interop between the "Kernel Flags" and "Kernel Architecture" flags of /L/P/S boot plist?

[ptesone]

iii. That is a good question