Also if I read this correctly (
http://www.appleinsider.com/article...ard_twice_the_ram_half_the_price_64_bits.html ) a 64 bit kernel is indeed actually important to improved performance.
"Snow Leopard will deliver both a 64-bit kernel and a full set of 64-bit bundled apps, erasing the entire TLB flush issue because the new kernel won't have to share any address space, even when running 32-bit apps (below right). This will benefit all 64-bit Mac users with a Core 2 CPU or better, even those lacking a Santa Rosa platform-style chipset, as being able to run 64-bit code and virtual memory is not tied to the amount of addressable system RAM."
Being in the know myself... K64 was not designed for speed. Anyone thinking that the purpose behind adding K64 is for speed improvements is going to be sorely disappointed.
The primary purpose behind K64 is to increase the addressable space in the kernel. This becomes important when you start seeing graphics cards with 8 gigs of VRAM or whatever years down the road. Again, this is straight from the horses mouth. Apple is not intending the addition of K64 to be a speed/optimization thing.
In addition, a lot of drivers are still missing in K64, so even if you did boot it, you likely would loose some of your hardware.
Consumers should not be booting K64 right now, at all.
How about just because he want's to? "Having a 64-bit kernel will [in the future as you say] enable Apple to move well beyond PAE to address very large amounts of installed RAM in Macs of the future as memory becomes more affordable. This is particularly useful for servers, but even consumer machines will someday need vast amounts of RAM.
...except the hardware memory controller in a rev A Mac Pro will never accept more RAM than PAE can address.
Additionally, the new 64-bit kernel will gain the advantages that 64-bit Mac OS X apps already have: the ability to set up an address space for itself greater than 32-bits (4GB), as well as the ability to access the full x64 register set of 64-bit CPUs. This wasn't as compelling of a need on the 64-bit PowerPC G5, but 64-bit Intel CPUs like the Core 2 Duo provide more general purpose registers that are conspicuously absent on 32-bit Intel CPUs, leading to a significant performance advantage when moving to 64-bit software.
Except no one out there right now is using more than 4 gigs of memory in the kernel space. Yes, people are using more than 4 gigs of memory in the application space, but not the kernel, and that will hold true for years to come.
The kernel being able to access the x64 registers is nice, yes, but generally there has been no significant performance advantage here. It can vary, but something like this is not going to really make Final Cut Pro render faster, or your games much faster. The kernel being able to access the extra x64 registers is going to have a limited impact.
And again, missing drivers still make K64 a non starter.
Along with these advantages comes the necessity of upgrading all of the kernel's drivers to 64-bit, including any provided by third parties. Again, that's because 64-bit programs can't load and run 32-bit plugins, and vice versa. That means Mac users will need to do the same driver upgrade that Windows Vista users did.
Which again, means that you probably should avoid K64...
Fortunately, Apple took steps to plan for the transition. By exposing 64-bit development tools and concepts years in advance, Mac programmers have had time to build a more mature understanding of how things work. If Apple had attempted to simply deliver a 100% 64-bit OS in one fell swoop, it may never have come together. Apple would have run into many of the same catch-22 problems that have held 64-bit Windows from gaining mass adoption.
Hahaha... Being a Apple developer who is in on this sort of thing, the original author of this article needs a clue stick. Apple had supplied 64 bit application development tools for the last few years, yes, but that's entirely different than supplying the tools needed to port kernel extensions and drivers over, which they have not done.
But yes, I was compiling my
application code as 64 bit at WWDC years ago. That's an entirely different bag of chips.
Additionally, Apple only needs to deliver a relatively small number of drivers: just those devices used in Macs supported by the Snow Leopard release. Since Apple designed and built all those machines, it won't have nearly as tough of a time as Microsoft had in prodding third parties to deliver good 64-bit versions of their drivers for all the hardware anyone has every put into any brand of PC sold within the last several years."
That's actually a large amount of drivers. In my day job I work with software that is very dependent on just the GPU drivers, and NVidia can't even get things working properly under 32 bit OS X. I don't expect their 64 bit OS X drivers will be very dependable. (NVidia actually pushes our software on their pro customers and they still can't get things right.)
And that's just the NVidia drivers. Every other drivers that makes it into K64 (which still isn't everything) is going to have an entirely new set of bugs.
Why anyone would want to run K64 in a production environment is beyond me. It's pretty much the new QuartzGL/Quartz 2D Extreme...
