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if you do a
ioreg -l -p IODeviceTree | grep firmware-abi

and it does not show EFI64 you will be unable to boot the 64bit kernel if you tried

yay for fabricated limitations!

On the other hand, BIOSes that run on 16-bit mode and have a maximum 1MB ram can run windows, linux and OSX's (hackintosh) kernels in 64-bit. Yay for oldies!

for me it makes the reason i got and waited to get my MBP pointless, wanted to put more memory in it, i can, but it wont use it all. and limited to 32 bit ( i dont care if the apps are suposedly 64bit, running on a 32bit OS makes it Emulated 64bit imo)

You make it sound like it's the end of the world.
While I don't know how it is in SL, there's no real technical reason why you can't. All it takes is a proxy that sits between the 32-bit plugin and 64-bit program. You can do this with Firefox on Linux, for instance.

But there is a technical reason. In-process extensions must be compiled for the same architecture. It is like this on every OS. With Safari they moved most extensions out-of-process to work around this, which is probably a wise thing to do anyway (Chrome already does this). Windows uses the same approach for certain kinds of extensions, like protocol handlers for the system indexer (so you can index 32-bit Outlook with the 64-bit indexer).

It's interesting to see Apple going through the same 64-bit growing pains that Windows dealt with ~5 years ago. It's hard to say if they're having an easier or harder time since they're transitioning so gradually. From my perspective it looks harder, since for most users the Windows transition has been so smooth as to be unnoticeable, as the parallel 64-bit releases since 2003 gave ISVs and IHVs lots of time to build up their support for it before machines actually started including it in stores over the last year or two.

for me it makes the reason i got and waited to get my MBP pointless, wanted to put more memory in it, i can, but it wont use it all. and limited to 32 bit ( i dont care if the apps are suposedly 64bit, running on a 32bit OS makes it Emulated 64bit imo)

I was under the impression that OS X was able to address more than 4gb memory since, at least, 10.5. Don't they use PAE for this?

for me it makes the reason i got and waited to get my MBP pointless, wanted to put more memory in it, i can, but it wont use it all. and limited to 32 bit ( i dont care if the apps are suposedly 64bit, running on a 32bit OS makes it Emulated 64bit imo)

That's not true at all. The kernel isn't the endpoint for all the applications that run on your system, and the kernel doesn't limit 64-bit applications in any way. In fact, there's virtually no difference in performance between the 32-bit kernel and the 64-bit kernel (look a few pages back for the Geekbench).

It's interesting to see Apple going through the same 64-bit growing pains that Windows dealt with ~5 years ago. It's hard to say if they're having an easier or harder time since they're transitioning so gradually. From my perspective it looks harder, since for most users the Windows transition has been so smooth as to be unnoticeable, as the parallel 64-bit releases since 2003 gave ISVs and IHVs lots of time to build up their support for it before machines actually started including it in stores over the last year or two.

Yea, it wasn't until Snow Leopard that developers had an easy way to develop and bundle their applications in 64-bit (Universal Binaries now accept 64-bit and 32-bit in one application). It's definitely been a more gradual change than the one Windows took, but it's seemed to work out. The only thing left back in the 32-bit world, for compatibility purposes, is the kernel, and you can make your kernel 64-bit if you know it's going to work out perfectly.

I'm not exactly sure which approach has worked better either. Snow Leopard definitely doesn't make a chaotic transition and, except for us technophiles, there should be no difference on the end users' side of things (except with maybe Safari and Mail input managers, if they use any).

OSX can use more then 4GB, but limitation of the hardware ( not processor, more mobo wise ) limits the addressable memory to the 32bit limit of 3.somethingGB, unless they are using special C2D's that are not the norm

put RAM in the Apple Support Discussions search box, alot of threads

I was under the impression that OS X was able to address more than 4gb memory since, at least, 10.5. Don't they use PAE for this?
OSX can use more then 4GB, but limitation of the hardware ( not processor, more mobo wise ) limits the addressable memory to the 32bit limit of 3.somethingGB, unless they are using special C2D's that are not the norm

put RAM in the Apple Support Discussions search box, alot of threads

The unibody MacBook Pros can use up to 8GB of memory. Same with the iMacs. The Mac Pro can support up to 32 GB on the 8-core and 8 GB on the quad core.

I'm new to having my own mac, as opposed to using one in college/uni for the last 5 years.

And I didn't feel I had enough time to read through all 83 pages.

I am getting Snow Leopard for the ?8 upgrade thing on the website, the macbook was bought by the uni and there was a bunch of uni related programs I don't intend to use with their bits and bobs, and odd files here and there.

With this upgrade disk, Will I be able to just erase everything and do a fresh install of Snow Leopard?

with all this talk of booting into the 64bit version of Snow Leopard is there a chance there is a compatibility list of apps ?

http://snowleopard.wikidot.com/start

That link's down at the moment, but is pretty comprehensive. Try again later.

OSX can use more then 4GB, but limitation of the hardware ( not processor, more mobo wise ) limits the addressable memory to the 32bit limit of 3.somethingGB, unless they are using special C2D's that are not the norm

put RAM in the Apple Support Discussions search box, alot of threads

I am aware of those limitations. Basically, some hardware other than the actual RAM modules are mapped to some portions of the 32-bit address space (4gb). That's the classical 32-bit limitation. Then you have other chipset limitations in the chipsets used by some macs. Some can't have more than 4gb installed, and some can't have more than 8gb.

But what I was talking about is that Leopard already had some 64-bit built onto it, and I was under the impression that it used PAE (physical address extension, that would allow a 32-bit OS to address more than 4gb ram). Granted, PAE is not ideal, but it does the job. If pretty sure that on my dad's iMac I can see the full 4GB in the activity monitor (or whatever it is called).

if you do a
ioreg -l -p IODeviceTree | grep firmware-abi

and it does not show EFI64 you will be unable to boot the 64bit kernel if you tried

By default yes that is correct, however the 32bit-EFI WILL boot the the 64bit kernel if forced by one of three ways, NVRAM, com.apple.boot.plist with arch=x86_64 added to the strings section, or holding the "6" and "4" keys on the keyboard during bootup

incorrect but im going by this as well as numerous other mac sites that are saying the same thing

all the tricks like the 6/4 are IF you have a 64EFI, otherwise you have to do the HAckentosh trick

By default yes that is correct, however the 32bit-EFI WILL boot the the 64bit kernel if forced by one of three ways, NVRAM, com.apple.boot.plist with arch=x86_64 added to the strings section, or holding the "6" and "4" keys on the keyboard during bootup
incorrect but im going by this as well as numerous other mac sites that are saying the same thing
Would you like to see what it is like to run in the 64-bit world? First make sure you have the right hardware for the job. Apple will only let you run 64-bit if you have a 64-bit EFI (see below for workaround). Here's a list of kosher Macs from the Snow Leopard release notes:

see that part where it says "see below for a work around" ? lol

the part below where it says THIS, Below is not IMMEDIATELY BELOW, everything imediatly below to the part i quoted below is for the 64bit EFI's

f you have a 64-bit processor but 32-bit EFI (for instance, users of the first generation Mac Pros amazingly have only 32-bit EFI firmware), there is still hope for you. From OSNews:

So, even if you have a 64bit processor, and you thought you were in the clear, Apple might not give you the option to go 64bit. However, in what probably rivals the Amazon Kindle 1984 thing in most ironic moment of 2009, the hackintosh community has come to the rescue. With netkas' pcefiv10.1 bootloader, you can boot into 64bi Snow Leopard even on 32bit EFI Macs. So far, it's not yet known if Apple will enable owners of machines with 32bit EFI to boot into a 64bit kernel in Snow Leopard-final; Apple might offer an EFI update, or remove the artificial limitation. The same applies to MacBooks; it might be that Apple is planning on using 64bit as a selling point to drive people to buy MacBook Pros instead of ordinary MacBooks..

Obviously using the Hackintosh hack to trick your EFI firmware ventures into the "use at your own risk" territory. That being said, have fun!

see that part where it says "see below for a work around" ? lol

unless you are on XServe you will not normally boot into the 64bit, you have to do the workaround

....so I hear snow leopard won't work with CS3?

Couldn't apple simply do a firmware update to enable that on (some) of the earlier intel macs?

They probably want to make it harder so people will just get a new mac...

They probably want to make it harder so people will just get a new mac...

Except it's not even a selling point right now because Snow Leopard defaults to the 32-bit kernel. Maybe a few years down the road, but certainly not now.

Do you know that for a fact or are you guessing?

Macworld:

The standard version of Snow Leopard is a bootable “full install” disc that doesn’t actually check for the presence of Leopard in order to install. This also means that if, at a later time, you want to wipe your hard drive and reinstall Snow Leopard, you won’t have to first install Leopard and then run a separate Snow Leopard upgrade on top of it. (That sound you hear is a thousand IT managers sighing with relief.)

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