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Why I dont feel bad about not booting into 64 bit Kernel


MacProUser83
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you probably won't want to boot into K64. But as Snow Leopard adoption ramps up and 64-bit updates of existing kernel extensions become available, why might you actually want to use the 64-bit kernel?

 

The first reason has to do with RAM, and not in the way you might think. Though Leopard uses a 32-bit kernel, Macs running Leopard can contain and use far more RAM than the 4 GB limit the "32-bit" qualifier might seem to imply. But as RAM sizes increase, there's another concern: address space depletion—not for applications, but for the kernel itself.

 

As a 32-bit process, the kernel itself is limited to a 32-bit (i.e., 4GB) address space. That may not seem like a problem; after all, should the kernel really need more than 4GB of memory to do its job? But remember that part of the kernel's job is to track and manage system memory. The kernel uses a 64-byte structure to track the status of each 4KB page of RAM used on the system.

 

That's 64 bytes, not kilobytes. It hardly seems like a lot. But now consider a Mac in the not-too-distant future containing 96GB of RAM. (If this sounds ridiculous to you, think of how ridiculous the 8GB of RAM in the Mac I'm typing on right now would have sounded to you five years ago.) Tracking 96GB of RAM requires 1.5GB of kernel address space. Using more than a third of the kernel's address space just to track memory is a pretty uncomfortable situation.

 

A 64-bit kernel, on the other hand, has a virtually unlimited kernel address space (16 exabytes). K64 is an inevitable necessity, given the rapidly increasing size of system memory. Though you may not need it today on the desktop, it's already common for servers to have double-digit gigabytes of RAM installed.

 

The other thing K64 has going for it is speed. The x86 instruction set architecture has had a bit of a tortured history. When designing the x86-64 64-bit extension of the x86 architecture, AMD took the opportunity to leave behind some of the ugliness of the past and include more modern features: more registers, new addressing modes, non-stack-based floating point capabilities, etc. K64 reaps these benefits. Apple makes the following claims about its performance:

 

250% faster system call entry point

70% faster user/kernel memory copy

Focused benchmarking would bear these out, I'm sure. But in daily use, you're unlikely to be able to attribute any particular performance boost to the kernel. Think of K64 as removing bottlenecks from the few (usually server-based) applications that actually do exercise these aspects of the kernel heavily.

 

If it makes you feel better to know that your kernel is operating more efficiently, and that, were you to actually have 96GB of RAM installed, you would not risk starving the kernel of address space, and if you don't have any 32-bit drivers that you absolutely need to use, then by all means, boot into the 64-bit kernel.

 

For everyone else, my advice is to be glad that K64 will be ready and waiting for you when you eventually do need it—and please do encourage all the vendors that make kernel extensions that you care about to add K64 support as soon as possible.

 

Finally, this is worth repeating: please keep in mind that you do not need to run the 64-bit kernel in order to run 64-bit applications or install more than 4GB of RAM in your Mac. Applications run just fine in 64-bit mode on top of the 32-bit kernel, and even in earlier versions of Mac OS X it's been possible to install and take advantage of much more than 4GB of RAM.

 

via www.arstechnica.com/apple

 

Hopefully people will stop bitching about not being able to boot into K64.

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you probably won't want to boot into K64. But as Snow Leopard adoption ramps up and 64-bit updates of existing kernel extensions become available, why might you actually want to use the 64-bit kernel?

 

 

Thats what I mentioned, but i just removed any 32 bit kext, tried booting with '-x64' and now i can feel a big difference!

 

I think this installation of OSX SL on my PC was easier than the previous Installation of 10.5

And its really faster with the 64 bit Kernel! ITunes opens in 3/4 of the time than it did before, for example.

Mail is like: Klick, its there(!!!), and I only have a GA EP35-DS3 + C2D 2,53GHz + NV8500GT + SATA Drives

+few Kexts +VoodooHDA everything 64bit,

and it costs less than a MacMINI, but has the power of a PRO...

 

Could Apple try to make it more accessible for PC users? to kill Microsoft?? nobody knows...

 

Well, I'm Happy!!! :-D

C'Ya

 

(All Kexts and instructions will be posted in another Forum in a few days!)

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Thats what I mentioned, but i just removed any 32 bit kext, tried booting with '-x64' and now i can feel a big difference!

 

I think this installation of OSX SL on my PC was easier than the previous Installation of 10.5

And its really faster with the 64 bit Kernel! ITunes opens in 3/4 of the time than it did before, for example.

Mail is like: Klick, its there(!!!), and I only have a GA EP35-DS3 + C2D 2,53GHz + NV8500GT + SATA Drives

+few Kexts +VoodooHDA everything 64bit,

and it costs less than a MacMINI, but has the power of a PRO...

 

Could Apple try to make it more accessible for PC users? to kill Microsoft?? nobody knows...

 

Well, I'm Happy!!! :-D

C'Ya

 

(All Kexts and instructions will be posted in another Forum in a few days!)

 

I'm glad to hear you have gotten 10.6 working, though how does this pertain to what he is talking about? Also I wouldn't look to apple releasing there os to pc users. Running a hackintosh is a great step into using a great OS, but all in all if you never buy a real mac then your no different then Uncle Gates. Supporting Apple is what keeps them developing a great OS, notice there Software improves as it evolves, Windows really doesn't scale that way, they fix one thing break 10others and call it a fix. Either way Apple makes great OS that is catered to their particular hardware. Would be happy to see as updates roll out and more 64bit updates roll out, but as previously said its for those people using software that takes advantage of it.

Don't take it personal, my main laptop was running osx86 from tiger days until about 2 months ago. Saved up long time, and this MacBook Pro 17inch 8gigs ram is by far the best investment i have ever made in any computer. Yeah they cost alot, but the quality is there.

 

Sorry to kinda jack your 64bit kernel post, just had to throw my two bits in.

 

"Apple kill Microsoft? Never, why would they kill off someone who gives them a slate of what people don't like. Think of Microsoft as the Beta and Apple as the Final, Considering Windows Really never goes final its always a beta."

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I agree! At least it makes me feel better for owning TWO brand new MacBooks and not one of them can run 64bit!

 

SticMAC

Oh, did I mention I have borrowed a client's 3 year old Dell XPS410 and it runs 64bit as default!

 

Best thread ever, I HATE people complaining about how they NEED 64 bit. Its total BS. 64 bit is garbage.
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I'm glad to hear you have gotten 10.6 working, though how does this pertain to what he is talking about? Also I wouldn't look to apple releasing there os to pc users. Running a hackintosh is a great step into using a great OS, but all in all if you never buy a real mac then your no different then Uncle Gates. Supporting Apple is what keeps them developing a great OS, notice there Software improves as it evolves, Windows really doesn't scale that way, they fix one thing break 10others and call it a fix. Either way Apple makes great OS that is catered to their particular hardware. Would be happy to see as updates roll out and more 64bit updates roll out, but as previously said its for those people using software that takes advantage of it.

Don't take it personal, my main laptop was running osx86 from tiger days until about 2 months ago. Saved up long time, and this MacBook Pro 17inch 8gigs ram is by far the best investment i have ever made in any computer. Yeah they cost alot, but the quality is there.

 

Sorry to kinda jack your 64bit kernel post, just had to throw my two bits in.

 

"Apple kill Microsoft? Never, why would they kill off someone who gives them a slate of what people don't like. Think of Microsoft as the Beta and Apple as the Final, Considering Windows Really never goes final its always a beta."

 

yeah! You are right! This is Why i'm switching step by step from Pc to mac.

I bought an Ipod Touch and à mac mini, but a mac pro is too expensive 4 me.

 

Apple should rule the world!

 

Peace

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