Snow Leopard always boots in 64-bit by itself...

[MikesGravity]

My Macbook always boots snow leopard into 64-bit mode by itself. If I hold down 3-2 when booting up, it boots 32. If I reboot, it's back to 64. I have 64-bit EFI and it's a unibody macbook pro.

Is this normal?? I thought SL only boots 32-bit natively?

 

[Surely]

http://www.apple.com/macosx/technology/

 

[Peace]

My Macbook always boots snow leopard into 64-bit mode by itself. If I hold down 3-2 when booting up, it boots 32. If I reboot, it's back to 64. I have 64-bit EFI and it's a unibody macbook pro.

Is this normal?? I thought SL only boots 32-bit natively?

You're confusing 64-bit apps with the 64-bit kernel. To see what you're using click on the apple logo and choose about this mac and on the left click on the software part. It will tell you if you are using the 64-bit kernel or not.

 

[MikesGravity]

Surely - thanks but that didn't help or answer my question at all.

Peace - I'm not confusing apps with kernel, it always boots the 64-bit kernel. Without holding 6-4 or anything.

 

[windels]

I thought that snow leopard doesn't have a 32 bit kernel? I think you are confusing it with leopard.

 

[stridemat]

I thought that snow leopard doesn't have a 32 bit kernel? I think you are confusing it with leopard.

Snow Leopard by default runs with a 32bit kernel. Most the apps run in 64bit and you can choose to boot the kernel into 64bit 'mode' for what good is does I do not know.

On the screen shot below most the apps have 64 bit in the 'kind' column, note the kernel is not.

 

[TuffLuffJimmy]

That's a really weird issue, OP.

@everyone else in this thread, you're all very confused. Snow Leopard does not normally boot with a 64bit kernel, unless you hold down 6 and 4 on boot up.

OP, did you maybe edit that plist (or whatever) that makes it boot into 64bit mode every time? Maybe you just forgot you did, or something...

 

[roadbloc]

I fail to see the issue. So what if it keeps on booting in 64bit or whatever. Welcome to the future.

 

[gibbz]

OP, use the Terminal app and edit this file

/Library/Preferences/SystemConfiguration/com.apple.Boot.plist

Change 'arch=x86_64' to 'arch=i386' (assuming it is currently set to x86_64)

 

[Denarius]

I fail to see the issue. So what if it keeps on booting in 64bit or whatever. Welcome to the future.

I believe that the issue is that not all kernel extensions have necessarily been rewritten to support a 64-bit kernel, hence the decision was made for Snow Leopard to default to 32-bit Kernel with the sole exception of a 64-bit kernel default on Xserves. 64-bit works, but can cause driver complications was my understanding.

 

[alphaod]

Go to —>About This Mac—>More Info…—>Software (AKA System Profiler)

Does it read 'Yes' or 'No' next to "64-bit Kernel and Extensions?"

ie: Mine reads 'Yes' indicating it's booted into the 64-bit kernel.

 

[LPZ]

OP, use the Terminal app and edit this file

/Library/Preferences/SystemConfiguration/com.apple.Boot.plist

Change 'arch=x86_64' to 'arch=i386' (assuming it is currently set to x86_64)

No. Just leave the Kernel Flags string empty, like this:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
        <key>Kernel</key>
        <string>mach_kernel</string>
        <key>Kernel Flags</key>
        <string></string>
</dict>
</plist>

 

[LPZ]

My Macbook always boots snow leopard into 64-bit mode by itself. If I hold down 3-2 when booting up, it boots 32. If I reboot, it's back to 64. I have 64-bit EFI and it's a unibody macbook pro.

Is this normal?? I thought SL only boots 32-bit natively?

What output do you get when you enter the following in Terminal?

/usr/libexec/PlistBuddy -c Print /Library/Preferences/SystemConfiguration/com.apple.Boot.plist

I get

Dict {
Kernel = mach_kernel
Kernel Flags = arch=x86_64
}

because I edited the plist to force my Mac Pro to boot using the 64-bit kernel by default.

 

[maflynn]

in the terminal type uname -a that will tell whether you're in K64 mode or using the 32bit kernel.

 

[chrono1081]

@OP mine does this too. Not sure why but I dont mind it I like 64 bit.

 

[gibbz]

No. Just leave the Kernel Flags string empty, like this:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
        <key>Kernel</key>
        <string>mach_kernel</string>
        <key>Kernel Flags</key>
        <string></string>
</dict>
</plist>

Either way works.

 

[LPZ]

Either way works.

Yup, you're right. Sorry.

The default is to simply leave the string empty.

 

[ItsAdot]

I'm no designer or anything else, just a daily user for mail, internet and basic stuff.

Should I change to 64bit? Or leave it at 32bit?

Thanks

 

[stridemat]

I'm no designer or anything else, just a daily user for mail, internet and basic stuff.

Should I change to 64bit? Or leave it at 32bit?

Thanks

No need for 64bit, stay with 32bit.

 

[Peace]

The only thing the 64-bit kernel will help at is video stuff that uses files bigger than 4GB.

But that in itself is no big boost because the Quicktime Authoring app is still 32-bit.

 

[ItsAdot]

Ok thanks

 

[MikesGravity]

Thanks for all the tips.

I know what I am talking about When I go to about this mac/system it says yes. I am booted in 64. I never altered my boot.plist file, the string is empty. But it kept booting into 64-bit.

I reset my pram and now it boots into 32-bit. It was a weird problem. My trackpad still isn't right. Not as precise as it was with leopard (documented on these forums, others have had this issue too).