2 versions of Snow Leopard?

[AndreaGalileo]

I have installed the "so-called" GM build 10A432 on my iMac 7.1.

I know i have a 64bit capable EFI. Even though, SL boots only in 32bit mode. I have tried pressing 6,4 on my keyboard but the OS still boots with a 32bit kernel and 32bit extensions. Adding this kernel flag: arch=x86_64 wont help either.

 

When I uname -a, i get this result:

xnu-1456.1.25~1/RELEASE_I386 i386

 

Have I installed a 32bit kernel only version of Snow Leopard?

 

Anyways, 64bit apps work great and fast. Great OS!

[mikecwest]

I have installed the "so-called" GM build 10A432 on my iMac 7.1.

I know i have a 64bit capable EFI. Even though, SL boots only in 32bit mode. I have tried pressing 6,4 on my keyboard but the OS still boots with a 32bit kernel and 32bit extensions. Adding this kernel flag: arch=x86_64 wont help either.

 

When I uname -a, i get this result:

xnu-1456.1.25~1/RELEASE_I386 i386

 

Have I installed a 32bit kernel only version of Snow Leopard?

 

Anyways, 64bit apps work great and fast. Great OS!

 

 

It seems like the 64 bit is only enabled on certain machines. Is an IMac 7.1 one of those machines? You can check the list below. (This list was found elsewhere on this forum in regards to build number 10a432)

 

It looks like your 7,1 is older than 8,1. It does not appear to be supported yet. My MacBook 2,1 SHOULD be able to use 64 bit, however does not appear on the list below and the steps that you took, also do not work for me.

 

 

Early 2008 Mac Pro

MacPro3,1

Capable

 

Early 2008 Xserve

Xserve2,1

Default

 

MacBook Pro 15/17

MacBookPro4,1

Capable

 

iMac

iMac8,1

Capable

 

UniBody MacBook Pro 15

MacBookPro5,1

Capable

 

UniBody MacBook Pro 17

MacBookPro5,2

Capable

 

Mac Pro

MacPro4,1

Capable

 

iMac

iMac9,1

Capable

 

Early 2009 Xserve

Xserve3,1

Default

[riws]

I have installed the "so-called" GM build 10A432 on my iMac 7.1.

I know i have a 64bit capable EFI. Even though, SL boots only in 32bit mode. I have tried pressing 6,4 on my keyboard but the OS still boots with a 32bit kernel and 32bit extensions. Adding this kernel flag: arch=x86_64 wont help either.

 

When I uname -a, i get this result:

xnu-1456.1.25~1/RELEASE_I386 i386

 

Have I installed a 32bit kernel only version of Snow Leopard?

 

Anyways, 64bit apps work great and fast. Great OS!

Do the File Inspection for Kernel "file mach_kernel".

mach_kernel: Mach-O universal binary with 3 architectures
mach_kernel (for architecture x86_64):	Mach-O 64-bit executable x86_64
mach_kernel (for architecture i386):	Mach-O executable i386
mach_kernel (for architecture ppc):	Mach-O executable ppc

[Chris Mills]

Do the File Inspection for Kernel "file mach_kernel".

mach_kernel: Mach-O universal binary with 3 architectures
mach_kernel (for architecture x86_64):	Mach-O 64-bit executable x86_64
mach_kernel (for architecture i386):	Mach-O executable i386
mach_kernel (for architecture ppc):	Mach-O executable ppc

 

PPC??? I thought the PPC code had been removed from the Kernel

[Duc-Man]

PPC??? I thought the PPC code had been removed from the Kernel

Hello

i have got this iMac:

Modellname: iMac

Modell-Identifizierung: iMac5,1

Prozessortyp: Intel Core 2 Duo

Prozessorgeschwindigkeit: 2.16 GHz

Anzahl der Prozessoren: 1

Gesamtzahl der Kerne: 2

L2-Cache: 4 MB

Speicher: 2 GB

and i installed the new SL10A432, but it works only in 32bit Mode.

the boot.plist i have already changed with "arch=x86_64"

boots always in 32bit-Mode

have anybody an Idea, how to fix it ?

 

lg

h

[Movi]

It looks like Macs that don't have 64bit EFI won't be getting 64bit kernel love. Even if they have a Core2Duo processor (My Macbook2,1 is one like that). Unless those macs get some kind of EFI update or Apple includes some kind of new boot.efi i don't see those Macs getting 64bit love. However, even tho the kernel will be 32bit, apps still run in 64bit mode.

[johnlocke2342]

I've got a Macbook 4,1 with both a 64 bit CPU & 64 bit EFI, and Snow boots with a 32 bit kernel.

[Chris Mills]

Wondering what my MacBook 5,2 will be (Early '09). I suspect it will be 32 bit Even tho it is C2D, and most definitely 64 bit EFI.

[AndreaGalileo]

It looks like Macs that don't have 64bit EFI won't be getting 64bit kernel love. Even if they have a Core2Duo processor (My Macbook2,1 is one like that). Unless those macs get some kind of EFI update or Apple includes some kind of new boot.efi i don't see those Macs getting 64bit love. However, even tho the kernel will be 32bit, apps still run in 64bit mode.

 

Well the iMac 7.1 (that is not officially supported for 64bit) has a 64bit EFI!

[namakemono]

Try booting with -x64.

I think PCEFI v10.x use those cmd´s, although they are also supposed to boot 64bit by default so maybe your puters not capable. I can boot mine in both modes, but use 32 since it works best on my machine..Some strange GFX kp`s

[AndreaGalileo]

Try booting with -x64.

I think PCEFI v10.x use those cmd´s, although they are also supposed to boot 64bit by default so maybe your puters not capable. I can boot mine in both modes, but use 32 since it works best on my machine..Some strange GFX kp`s

 

I'm talking about getting 64bit on a REAL mac

[pmcnano]

Maybe it loads only 32bit atm because of the missing 64bit kexts (for example airport..)

[Synaesthesia]

32 bit kernel can load 64 bit kexts

[CTJoyce]

My Late 2008 Macbook5,1 loads the 32 bit kernel, however I remember reading an article that stated you could force booting into the 64 bit kernel by holding the 6 and 4 keys on startup, however doing this still would seem to be booting my mac into the 32 bit kernel as my output is xnu-1456.1.25~1/RELEASE_I386 i386

[thorias]

Thing also a lot of third parties kext are still compiled in 32bit so right now it's better to run snowleo in 32bit for max compatibility with apps....

[Ritsuka]

A well written comment about the new kernel:

http://www.osnews.com/permalink?379368

Why everyone is believing what Holwerda, who seems more and more into the trend of bashing Apple, is saying, because the mater of the fact is that he does not know what he is talking about?

 

I first have to wipe out the misunderstanding that people have here mostly because of poorly minded guys writing on the web.

 

Mac OS migration to 64 bits is in fact well smoother and sophisticated than it is on Linux or windows (which did not any transition per say, more on the matter later) and the architecture has allowed to build applications and drivers for both 32 and 64 bites hardware. But before to dig into that, few words about the reality of the 64 bits advances on OS X.

 

The first 64 bits support was introduced in Tiger at the Unix level, so that any command based application (very often used in scientific workload for example) could get access to 64 bits addressing and arithmetic. It was possible to build the binaries for both 32 and 64 bits, for both powerpc and intel, all together into one Mach-o object file, all running on the same unique OS. This allowed developers to target many architectures and still providing one binary visible to the user, the OS loading the appropriate bits.

 

Leopard completed the 64 bits transition as far as it comes for developers to build 64 bits apps. All the OS stack was transitioned to 64 bits, including Cocoa, OpenGL, Quartz, etc, only UI Carbon was left over as obviously it did not make any sense for Apple to continue to support it. With Leopard, any application can be build for support of 64 bits addressing and arithmetic.

 

Note that in Leopard too, applications are compilable into one single Mach-O object file that contains the binaries for 32/64 bit powerpc, 32/64 bits intel. And in comparison to windows or linux, this model was way more elegant for users as they did not have to bother to know which OS they have or if their app is 32 or 64 bits, or if it will run at all. On Windows, the messy transition have forced users to install another OS, specific app for 64 bits (if available), the same on Linux. This has highly reduced the speed of the transition as for example on Windows, 32 bits apps do not run natively on win64 but on an additional layer that reduce performance.

 

Different OS running different applications is really not the model that anyone with some good sense would defend (well besides strange guys like Holwerda i guess), the user should never know how the app that he/she wants to use is compiled . Most of them do not really know what 32/64 bits means anyway, and Microsoft or Linux forcing the user to bother with it is simply insane.

 

On Leopard, the kernel was still 32 bits (a kernel does not need to be 64 bits to run 64 bits apps with the magic of OS X). With Snow Leopard, the new 64 bits features are for two things:

 

- First almost of all the system applications are compiled in 64 bits.

 

- The kernel is 64 bits.

 

Having the applications compiled in 64 bits allows to take advantage of the additional registers of the X86_64 architecture which can greatly improves performances. It also allows to leverage some new security technologies by default.

 

The 64 bits kernel serves several objectives:

- It allows for larger address space allowing better performance of server workloads. It takes 64 bytes to describe each 4k page of RAM, so with 96 GB of physical RAM, this means that 1.5 GB of kernel virtual address space are used just to describe the physical memory. With having to store many more information, Vnodes, VM data structures, process data structures, etc, the kernel will soon run out of adress space for such high end configurations. Hence, the need for 64 bits addressing in the kernel.

 

- It improves the system call, 250% faster on k64 than k32 which results in a 70% performance improvement in user/kernel memory copy.

 

- It allows to increase the OS ressource limitations. On K32, 2500 processes are allowed in the system, on K64, the limitation is dynamic as the number of processes that the system can handle scale with the physical RAM available, 96 GB allowing for example 30000 processes.

 

So that's how the 64 bits world has evolved in OS X, note that 64 bits apps are 100% compatible with the 32 bits kernel (try to find that on windows, Holwerda, with microsoft or linux you need to install a different OS,....) because the 64 bits kernel has the same user-kernel interface as the 32 bits kernel. That also means that the transition to 64 bits at Apple was not an after thought as it is at Microsoft.

 

As you can see, for Snow Leopard all users will benefit from the 64 bits compiled system apps. For the 64 bits kernel, Apple needs its developers developing KEXTs (that is also low level drivers) to build 64 bits KEXTs. The 64 bits kernel will only be available as default in the Xserve as this is where it make the most of sense. Usual users really do not need a 64 bits kernel, as its benefits are for the moment only visible in the server space and workload, everything else is marketing.

 

And this also where OS X does much better than Linux or Windows. The 64 bits kernel needs 64 bits KEXTs because the different address mapping, but the kernel is flexible enough as it allows developers to build KEXTs for multiple architecture. It is possible to build both 32 and 64 bits KEXTS that will be loaded by the kernel as needed, 32 bits KEXTS loaded in a 32 bits kernel and 64 KEXTs being loaded in a 64 bits kernel. Again the user does not need to know if his/her low level driver is compatible or not, 32 bits or 64 bits, the platform abstract the complexity. This is absolutely not the case on Windows or Linux, users have to check if they are getting the good driver, assuming that they know what 32 and 64 bits means (few of them know, my wife does not), well brushing their computer science knowledge in some sense.

 

Building for K64 is also quite easy, most of the time a recompilation is enough if the non-depreciated KPI are used.

 

So here we are, i hope that i bought some light in the Holwerda's disinformation. Holwerda, you don't know what you are talking about, i say you that straight.

 

" Only Macintosh machines with a 64bit EFI are able to boot the 64bit Snow Leopard kernel and kexts; this is an artificially implemented limitation by Apple, as 32bit EFI can boot a 64bit kernel just fine."

 

Wrong don't talk about things that you don't understand. A 32 bits can indeed boot a 64 bits kernel, but Apple needs the 64 bits EFIs for some low level kernel operations managing the universal KEXT architecture.

 

"On top of that, even if your MacBook has a 64bit EFI, you will only be able to boot the 32bit version of Snow Leopard - again because of an artificial limitation by Apple for MacBooks."

 

This is not a limitation but a technical requirement. Apple needs to have 64 bits KEXTs (including low level drivers) so that users who depend on them can continue to operate their devises. Snow Leopard come with Apple's KEXTs compiled in 32 and 64 bits mode, they still need to wait for third party developers to make the jump. For the end user that does not change anything, users of macbooks benefit a little of a kernel in 64 bits.

 

"Probably the harshest consequence of this is that the original Mac Pro, discontinued January 8, 2008, cannot boot the 64bit kernel and drivers."

 

This model had an 32 bits EFI because it had to do with some issues with some GPUs firmwares available at that time for mac. I don't know if Apple will make available an EFI update for this machine, but if not, it is not a big deal. Even this machine is far from hitting the limit of a 32 bits kernel, and again you can run all application in 64 bits. So no problem, the other things is your imagination {censored}.

 

"With netkas' pcefiv10.1 bootloader, you can boot into 64bi Snow Leopard even on 32bit EFI Macs."

 

Again, you miserably miss the point for instead promoting sensational informations. This sort of hack may cause low level issues with the architecture of the kernel for supporting universal KEXTs.