64-bit Snow Leopard defaults to 32-bit kernel

Apple's Snow Leopard operating system, released Friday, by default loads with a 32-bit kernel, despite running 64-bit applications.

While Mac OS X version 10.6 ships with a number of 64-bit native applications, the kernel itself defaults to 32-bit, unless the user holds down the "6" and "4" keys during boot time, at which point the 64-bit kernel is loaded. Only Apple's X-Serve products, using Snow Leopard Server, boot into a 64-bit kernel by default.

"For the most part, everything that they experience on the Mac, from the 64-bit point of view, the applications, the operating system, is all going to be 64-bit," Stuart Harris, software product marketing manager at Apple Australia said.

Harris said that at this stage there were very few things, such as device drivers, that required 64-bit mode at the kernel level but the option is available.

"But we're trying to make it as smooth as possible, so people don't end up finding that 'oh, that doesn't work' because it's not available yet," he said.

There appears to be no way within the GUI to make this change permanent, requiring the editing of the com.apple.Boot.plist file to make the change--a text-based configuration file. Users have already released applications to address this issue.

Older Macs with a 32-bit EFI chipset are prevented from loading the 64-bit kernel, although there are claims that this is an arbitrary decision by Apple rather than a technical concern, with a hack using the Chameleon boot loader devised to get around the lockout.

An older mid-2007 MacBook with a 32-bit EFI chip can't register the full 4GB RAM.

(Credit: Screenshot by CBS Interactive)

This raises another problem: if equipped with 4GB RAM, those with a 32-bit EFI chip are not capable of making use of the full amount. Our mid-2007 MacBook only showed 3GB available for system use through Activity Monitor despite having 4GB installed, not delivering the true 64-bit experience. Newer machines equipped with a 64-bit EFI chip running a 32-bit kernel seemed capable, with Activity Monitor reporting 3.75GB RAM available, as 256MB was put aside for the GeForce 9400M graphics chip.

It is unknown at this stage what sort of performance implications running 64-bit applications on a 32-bit kernel will have compared with a 64-bit kernel.

While a large portion of the OS has been optimized and updated, some applications, such as the DVD player, Front Row, Grapher, and iTunes are still 32-bit only, and some extensions are still run as a Universal Binary, despite the PPC architecture no longer being supported.

Apple also released Snow Leopard Server on Friday, but was unable to detail the reasoning behind dropping ZFS support for the operating system, a much-touted feature during the development stage.

Some processes are still running as Universal Binary.

(Credit: Screenshot by CBS Interactive)

Craig Simms of ZDNet Australia reported from Sydney.

[Gold_Storm_Mac]

its nice to have the option.

[weedmonk]

So this a feature. The stuff you guys have to rationalize for the "Worlds Most Advanced OS" gets downright hilarious at times. Snow Leopard gives you novelty version of x64 computing. If I'm not mistaken Adobe CS4 will be Windows x64 only as well.

[Seaspray0]

But why default to 32 bit? Why not default to 64 bit? Can anyone explain that?

[Police_States_of_America]

because apple realized they could sell low spec macs at high prices to itards

[Mr. Dee]

Another example of the gimmick that is Mac. The way how they were touting 64 bit, you would swear it was the second coming of Christ. Now all those 64 bit Macs are just under performing because the OS remains immature, and there are many out there because I read the forums, check out my 4 GB 24" iMac, check out January 2008 6 GB of RAM Mac Pro.

Sorry, too bad you won't be able to use it. Well you can, just load Windows 7 64 bit on the darn thing and put it to good use.

[sevort]

Yeah, right. So take a look at "64bit" Window 7. It's a monster that still has not only 64 and 32 bit chunks of code, but even 16 bit as well!

[Mr. Dee]

@sevort Are you that clueless when it comes to computers? Microsoft removed the 16 bit subsystem from Windows starting with Windows XP Professional x64 (April 2005), back then Apple was still pushing its early gimmick named Tiger that still had to depend on the old dilapidated Classic Mac OS 9 environment to get ahead.

[stickfu]

Sorry Dr Shillinger Tiger never needed OS9. You should do some research before you post.

[stickfu]

Sorry Dr Shillinger Tiger never needed OS9. You should do some research before you post.

[Gold_Storm_Mac]

if it wasnt in 32 bit mode then all the drivers and apps that are in 32 bit wouldnt work with a 64 bit kernel. this is for compatibility. better than choosing between either a 32 bit or 64 bit OS like with windows. all the apple apps are in 64 bit so it still has those speed improvements.

[SolarSaves]

The funny thing is that 90% of all computer users in their normal computer use will never notice the difference between 32 bit and 64 bit. Whether Windows, Mac or Unix and its variants... OMG its only 32 bit so it is going to suck! Get over it nerds!

[contentcreator--2008]

If Snow Leopard doesn't default to 64-bit mode and can only be started by extraordinary action with a 64-bit kernel, what's the point? Leopard already runs 64-bit apps on a 32-bit kernel. This means that OSX is still not equivalent to ancient XP -64 or Vista-64 in its 64-bitness. Going full 64-bit was supposed to be one of the (few) selling points of Snow Leopard. Another brilliant Apple marketing ploy ---- "we'll make it 64-bit, but not let you start it., yeah that's the ticket"

The performance hit is when you start your first 64-bit application --- OS X grinds a bit as it loads up 64-bit versions of various libraries. If Snow Leopard stays 32-bit, that means it will still have both 32-bit and 64-bit versions resident, burning off more of your RAM compared to having all-32 or all-64.

[aaanandhismini]

It's just to let people get up to speed with drivers and such, relax dude.

The sky isn't falling and puberty will end, trust me.

[rfelgueiras]

"While Mac OS X version 10.6 ships with a number of 64-bit native applications, the kernel itself defaults to 32-bit, unless the user holds down the "6" and "4" keys during boot time, at which point the 64-bit kernel is loaded."

Right there, in the second Paragraph... let's try that one more time:
"the user holds down the "6" and "4" keys during boot time, at which point the 64-bit kernel is loaded."

Not all Macs with intel chips that can run 10.6 are 64 bit. Why start in it by default?

[ikramerica--2008]

It is very likely that Apple will "turn on" 64-bit kernel within the next 12 months by default with a dot update, once drivers are prolific. Until then, they will give customers the option.

Windows had no option. You either installed 64-bit or 32-bit Windows, and that was that. Having a simple toggle is more elegant.

Anyway, THIS IS NEWS???? It's been known for weeks and months...

[T_Hoff]

@rfelgueiras
>> Not all Macs with intel chips that can run 10.6 are 64 bit. Why start in it by default?

Because on hardware not capable of running 64-bit code, you wouldn't start it -- ever. Not even if you hold down "6" and "4".

[ballmerisanape]

Also.. all of the reviews that I have read so far say that SN is significantly "snappier":

PC Mag:
http://www.pcmag.com/article2/0,2817,2352066,00.asp

InfoWorld:
http://www.infoworld.com/d/mac/mac-os-x-snow-leopard-perfection-refined-364

Forbes:
http://www.forbes.com/2009/08/27/apple-operating-system-technology-enterprise-snow-leopard.html

[timber2005]

@rfelgueiras "Not all Macs with intel chips that can run 10.6 are 64 bit. Why start in it by default? "

Irrelevant... you won't be running 64-bit apps if your processor doesn't support 64-bit... whether the 32bit kernel can or not.

[Hep Cat]

"Extraordinary action"?

Changing the boot arguments is extraordinary?

[cloudmatt]

first if it's going to be a dual mode system(64 and 32) that's cool bout time they caught up with the real world. they are doing it wrong but cool. just run the 64 bit kernel with 32 support. oh wait it uses an Intel chip.

solution, Apple starts useing dual mode chips like AMD's. then they could run a native 64 bit platform that can operate all 32 bit commands with out emulation. I've been doing this with windows since the amd fx-55. welcome to the game apple try and keep up.

[texaslabrat]

@cloudmatt:

Apple *IS* using "dual-mode" chips...they are the same processors that go into PC's which handle the dual-mode thing just fine under Linux and Windows (intel calls theirs "EMT64"). It's just the geniuses at apple thought that it was better to "thunk" upwards rather than downwards. Probably because they had painted themselves into a corner by selling hundreds of thousands of laptops with intel chips but no 64-bit capabilities (the original intel "core" cpu's) that they felt they couldn't afford to alienate. Unless there is hardware support for such "reverse-thunking"...I would imagine there's a measure-able performance hit here.

[Super2online]

For a company that prides themselves on creating well oiled and finely tuned machines, it appears they couldn't figure out how to do it without creating a less than perfect solution. An implementation that's obviously not up their standards.

[veggiedude--2008]

It makes perfect sense for Apple to do this. Next year, third party vendors will have enough time to catch up with the technologies in Snow Leopard. In the meantime, for better compatibility, the Macs should boot into 32-bit mode. If we really want 64-bit and don't want to hold down the keys, edit the plist file.

Snow Leopard is designed not for today, but for the future. Software makers have to redesign their apps to be able to access up to 16 Billion GB of memory, and to handle multiple processors (now simplified in Snow Leopard). It can handle 16 thousand gigabytes of RAM. No machine today exists to take full advantage of it.

[Thranx]

"It makes perfect sense for Apple to do this. Next year, third party vendors will have enough time ..."

While that statement makes alot of sense, and I would normally agree with you... 3rd party vendors had over a year's worth of access to Vista and they still were completely irresponsible in drive support. IMO 75% of vista's poor perception in the market place is due to irresponsible hardware vendors... and that wasn't even a architechure change like 32->64. Yes, the sound and print engines were completely overhauled, but there was PLENTY of time in advance. (I was working in the software QA division of a large printer company at the time... they didn't even touch vista until a month before RTM. Bad.)

A stages approach like this will soften the blow to the end user, and that's good, but it's not going to kick any 3rd party vendors in the pants and get them moving.

[gggg sssss]

@Thranx some windows programers wish we still has DOS. Doent make them right. Or relevant

[MadLyb]

So, 64 bit is a cheat mode?

I wonder if there are other cheat codes that unlock additional functionality.

[man_w_balls]

yes, Command-S unlocks "god" mode

[ikramerica--2008]

lol

[mudphud]

"up up down down left right left right b a start" gives you 9 free restarts

[GDEsplin]

I don't get it. So the 64 bit apps won't really be 64 bit unless you start it 64 bit mode? If I leave it in 32 bit mode will it still be the "2x" faster?

[ballmerisanape]

64-bit apps.. including the Finder.. will still behave like.. and will be.. fully 64-bit. This really is a non-issue. The real issue here is why they dropped the ZFS file system.

[darthstupid]

Maybe they dropped ZFS because Sun was bought by Oracle putting the future of ZFS into limbo.

[ikramerica--2008]

64-bit is not 2x faster. Anyway, 64-bit is mostly for addressing memory over 4GB for any one application. Currently, anything over 4GB installed is still expensive and most users don't have the need for it. But the option is there to run the Pro in 64-bit mode, the XServe defaults to it, and those who really want to run their Macbooks in 64-bit can do so, just don't expect to print to some printers (just like when Windows started with 64-bit).

[aaanandhismini]

You people are lost. Please read up on the issue (and I mean read more than just this article) an app that launches in 64 bit mode is running in 64 bit mode. That is that.

Man, this is getting sooooooo over blown and by people who do not know s@#t about it.

Do any of you know why you might even need 64 bit computing? anyone?

Though so.

[ewsachse]

Stop being the biggest Apple apologist out there. Apple advertised 64 bit, but they lied. Pressing 6 and 4 while booting is just plain retarded.

Even Linux handles this more gracefully than Apple.

A sucker is born every minute.

[jimmyblake]

@ewsachese ...and of course Linux would never require to manual editing of a text file would it?

[darthstupid]

No kidding. Most people here seem to think it's like the old days of video game systems.

"Man my 64bit Jaguar is sooo totally more extreme than your 16bit Genesis!"

64bit is currently relevant to only a handful of people, mostly researchers and people doing high end graphics work. Beyond that it is a marketing term (for now).

[philosfool]

Well, if you want your OS to be able to address more than 3.3GB RAM, you might want a 64-bit OS. This hasn't been a problem for Apple in ages, but for Windows users who are actually shelling out money at Best Buy for 4GB of RAM, getting 32-bit windows is a bit dumb.

[ikramerica--2008]

Actually, Leopard could use all 4GB of physical RAM for applications (and system), offloading the "address space requirements" of the system to a second, phantom 4GB. This is under 32-bit mode.

So what 64-bit really provides on Snow Leopard is the ability for any one application to use more than 4GB of physical memory. And I don't know who needs that other than Photoshop users, video editors and scientists. Photoshop is not yet 64-bit and won't be until CS5, I don't believe FCP is yet either, and scientists can turn on 64-bit knowing that they won't have full kext support, but the don't care...

[CantonWebStudio]

ikramerica,
Photoshop cs4 also comes in 64-bit. Please research facts if you are going to state them.

[TheForestFloor]

64bit code isn't just about memory addressing. While it's true that you can address more physical memory, the cores themselves have components (ALU, FPU, DMA controllers, etc) that have both 32 and 64 bit registers and instructions. One of the biggest benefits of using 64bit code is that you get to take advantage of the larger register set (which allows for more code to be loaded into the core at once), access to hardware implementations of common functions (especially math functions like sin and cos), use of advanced features like sse4 and the like. One of the best, but yet unspoken features of the cores having both 32 and 64bit registers and instructions is that both sets of hardware can run *at the same time*. While the 64bit registers and components are working on code that will benefit, the 32 bit components are not idle... They can crunch things that don't require high precision. That is what is mainly responsible for increased performance of 64bit code.

While it is commonly said that only people who *need* > 4GB of memory are the only ones who benefit, that is totally false. Simple functionality like decryption, loading and decoding jpeg images, playing movies, modifying images all take advantage of this increased functionality. Three of the most processor intensive operations (DFT, or Discrete Fourier Transform, DWT, Discrete Wavelet Transform, and DCT, Discrete Cosine Tranform) are heavily used throughout the system to perform the above tasks. They all make heavy use of trigonometric functions, which must be implemented in software on 32bit machines, which can take hundreds of cycles to perform. G5s and x86_64 chips have these functions (all based on the hardware cos function) and can perform the same action in only one or two cycles. That means playing iTunes while rendering in Final Cut or number crunching in Matlab will take less time and consume less power. Same goes for games, web browsers (which need to play video or display images), screen savers and the like. Once developers really start including OpenCL into their code, not only will both the 32 & 64bit chip components be working at full tilt, but extra capacity of the graphics cards can be brought online too.

64bit will be a Good Thing for all users. However, that doesn't mean it's always necessary, or crucial that people have it *right now*. Having 32bit code isn't a Bad Thing, nor is having a mix. It wasn't crucial for all 16biters to immediately have 32bit support, and it's not true that everyone needs immediate access to all of the 64bit 'goodness' that can be had. Eventually, 64bit will be the standard, and companies will tout the need for newer, faster 128bit chips.

[DrtyDogg]

@canton: Not on OS X

[ikramerica--2008]

Canton-

Please research your own facts before correcting someone, lest you look like a tool.

[man_w_balls]

This is clearly something that will need to be addressed with an update. Right now, with old Leopard, I can address my full 4GB of RAM, and I don't have the 64-bit EFI chip.

[danielwsmithee]

You can address your full 4 GB in Snow Leopard too. The 32 vs. 64-bit kernel has nothing to do with whether or not your computers chipset can address upto 4GB of memory. In 2007 the Core 2 Duo MacBooks contained a chipset that could only address a maximum of 3 GB of RAM. That is a limitation of the chipset for those laptops, Leopard vs. Snow Leopard won't change that.

[aj37viggen]

Before people start getting their underwear all bunched about this, they should read the "Common Misconceptions" section in Apple Developer Connection's "64-Bit Transition Guide:"

http://bit.ly/5AHTH

Short summary: while 64-bit gives programmers valuable options, it's not correct or realistic for users to assume that 64-bit [whatever] is necessarily better than 32-bit [whatever.]

Or as Adobe's John Nack put it in an entry in his <a href="http://blogs.adobe.com/jnack/">blog</a>: "Please stop asking for a 64-bit version of iTunes or DVD Player or Fireworks or whatever, blindly assuming that /number of bits' equals 'goodness.'"

[basraw]

lets go back to 16 bit vigger

[TheForestFloor]

I think there's a technical disconnect here.

If you boot into a 64bit kernel, none of your 32bit device drivers will work, so people who are upgrading will struggle. Drivers built for snow leopard will have both 32 & 64 bit code, but until that happens, booting into 64bit by default isn't the right way to go.

That said, 'booting into 64bit' only refers to the kernel. All of the other libraries that apps depend on, AppKit, FoundationKit, libc, etc are all 64 bit, and will load if a 64 bit processor is accessible. Also, any program that was compiled with 64bit code will run in 64bits period, giving you that (2x) improvement.

The biggest problem for users will be that their software (Photoshop, Logic, etc) will be 64 bit, but their plugins might not be. If any program has plugins or extensions that are not 64 bit, it will have to be relaunched into 32bit mode to use them. Contrary to contentcreator's comments, OSX does not 'grind a bit' when loading 64 bit code, nor does it load BOTH 32 and 64 bit. It loads 64bit code if it's dependent libraries and the processor support it. If not, it degrades gracefully (and speedily) to 32bit code.

That said, nearly all programs 32/64/ppc continue to run well on SL, and all of them get to take advantage of GCD when they run, so they run a bit faster as well.

In the pre-release versions of SL, all of the Macbook Pros, Mac Pros and XServes could be set to boot in 64bit by default (without 32bit device drivers), and the others (with the exception of the MBA and Mini) could be booted with the '64' keys held down. I guess they removed it to keep users from getting confused if their devices stopped working. My guess it will be the default for all machines once the driver community has moved all of their code over.

[ballmerisanape]

You should have written this article. Thanks for that very clear explanation... i'd like to believe that this is just another "hit piece" article.. but im guessing.. in this case.. the author just didn' t know what the heck they were talking about.

[myles taylor]

Thank you for that. People are going to flip about this and they don't even understand what it means.

[darkxeno]

Dear God some one here Knows what they are talking about. Once I heard about this I started digging around. To me this make total sense that they did this. I don't care if your PC or Mac 80% of the users of the system don't understand what goes on under the pretty pictures they see on the screen. So in order to save some headaches they did it this way. Im sure within two or three updates they will change over to total 64bit once software makers have gotten onto the wagon more then they are now.

[krushyou]

Wait a minute...If Apple discontinued PPC support how is a ppc program going to run? I am confused...

[krushyou]

Crap, nevermind someone else answered it below...

[Vegaman_Dan]

A thoughtful response that is logical, well put together, and doesn't have any agenda pro or con.

Please post more often.

[martin1212]

"Also, any program that was compiled with 64bit code will run in 64bits period, giving you that (2x) improvement."

Er, 64 bit does not give 2x improvement. I can't believe people are still saying that. Makes it hard for me to take anything else you wrote seriously...

[Endbringer]

Nice post, except for the 64-bit being twice as fast as 32-bit.

[mpitogo]

Some here just don't get it. 64bit and 32bit are installed under the same OS umbrella. With WIndows XP you either have 32bit or 64bit. I can't just reboot my XP and whoosh have XP64 you simply can't boot into either one without having two OSs installed and dual booting. I think its the same case with Vista, you're either 32 or 64bit not both. I wish I could boot my XP into 64bit mode. It'll take better advantage of the IntelVT technology I have running with VMware.
And another point unlike Microsoft, Apple's main concern was first have a stable transition. Functionality over features. The users' need to maintain compatibility with older hardware which may not be ready with 64bit drivers is very important. The experience in 32bit with functioning hardware is much much better than a marginally better 64bit experience with some possible driver issues. If you take vista for example how many upgraded right off the bat with little concern for their device drivers only to find out it doesn't work.

[texaslabrat]

Um, yes windows works as "both" just as much as SL does...you load a 64-bit kernel and "woosh" you can run 64-bit apps AND 32-bit apps. Ditto Linux. I think it is you who doesn't "get it". While it's true that you can't arbitrarily choose which one without a re-install (or some heavy-duty customization magic) in windows/linux...that's a bug not a feature that Apple is using as a crutch. If done correctly, you wouldn't NEED to be able to choose which kernel mode to use...you would just 64-bit and let the 32-bit and 64-bit apps and drivers do their thing. Since they have to rely on such "trickery", it's clear that something is amiss ;)

[rsfinn]

"...some extensions are still run as a Universal Binary, despite the [PowerPC] architecture no longer being supported."

Snow Leopard does not support installation on PowerPC machines, but does continue to support the Rosetta environment to execute older PowerPC-based applications. No doubt that is why some of the lower-level kernel extensions (e.g. "BSDKernel") continue to be supplied as Universal Binaries.

"Apple ... was unable to detail the reasoning behind dropping ZFS support for the operating system, a much-touted feature during the development stage."

Leaving aside the question of who was doing the touting, the short answer seems to be that the ZFS port to Mac OS X wasn't complete and is missing some functionality critical to the Mac user experience. See here: http://bit.ly/1LKDvA

[ikramerica--2008]

I chose to install Rosetta, and I'm running Adobe CS and OfficeX just fine, both apps that were written for PPC.

[brandonc09]

This article implies that Snow Leopard runs only in 32-bit, which is incorrect. Only the kernel is running in 32-bit mode. This is done for extension/application compatibility. A 64-bit application such as the Finder or Safari is still 64-bit.

[warpsix]

Had this been Microsoft the above comments would have been very different

[sanenazok]

Well the reason for this is obvious: device drivers. Apple can just say "no 64-bit for you" and continue to use the same old OS X drivers. Much of the bellyaching over Vista has been lack of drivers. What's sad is given the number of devices for Apple they should have taken care of it. I guess that's what happens when you stop being a computer company.

[FellowConspirator]

If you go through the console messages you'll note that it switches to 64-bit during boot if it can. You'll also note that the reason that the Macbook cited in the article can't register mores than 3G of RAM isn't a function of the Snow Leopard kernel or the 32-bit EFI, but rather it's the result of using the Intel 945 chipset.

If you want to force it to boot 64-bit, first go to the terminal and check that you've got a 64-bit EFI. In the Terminal, type:

ioreg -l -p IODeviceTree | grep firmware-abi

... if you see "EFI64" then you are good to go. Next, you should boot using the '6' and '4' method and verify that all your devices work fine (most common things should). If everything checks out, you can force booting in to the enable that with this (in the Terminal):

sudo defaults write /Library/Preferences/SystemConfiguration/com.apple.Boot 'Kernel Flags' 'arch=x86_64'

You can also directly set the boot flags:

sudo nvram boot-args=?arch=x86_64?

or

nvram boot-args=?arch=i386?
This has the effect of forcing the 64-bit kernel load. The practical upshot is that the system will only be able to use 64-bit drivers, which may or may not work for you, depending on what you've got.

You don't need the 64-bit kernel to load in order to run 64-bit applications or to access >4G of RAM. Conversely, if you've got a machine with an Intel 945 chipset that doesn't address >3G of RAM, there's no software magic at all that will fix that. Booting the 64-bit kernel only only has the effect on whether it loads the 32-bit or 64-bit version of a kernel extension or device driver. Right now, there are a few 32-bit only device drivers, but no 64-bit only ones. Presumably this is why the default was chosen as it was.

Incidentally, if you screw up and find out that you set the machine to boot 64-bit when it can't, you can use the logical step of holding down the "3" and "2" keys to boot into a 32-bit kernel.

Jus' sayin'.

[ikramerica--2008]

And just to be clear:

Core Solo/Duo macs: 2GB RAM max due to HARDWARE limitations
Intel 945 chipset macs: 3GB RAM max due to HARDWARE limitations
Core 2 Duo Santa Rosa and above, Xeon hardware: 4GB+ (6GB max for Santa Rosa, not 8GB, but not positive that is hardware related or that Apple would not enable more than 6GB because Leopard can't address more than 6GB)

[Seaspray0]

Good info, Fellowconspirator.

[TheForestFloor]

I'm glad this thread hasn't turned into a balls-out flame war, but the point is this: Snow Leopard continues the 64-bit transition, its not a magical 'switch'. Apple seems to want to make the transition as transparent as possible for as many users as it can, period. No software can be all things to all people all the time, but Apple has tried to push things forward in stages so we can all reap the benefits when the time is right. 10.4 offered 64bit command line apps, 10.5 offered a 64bit GUI, and 10.6 offers a 64bit kernel; when the offerings first became available, users and coders needed time to catch up. That will probably not change in the future, so have patience and be careful with your upgrades (especially if your computer is your livelihood). Seriously.

If you upgrade to SL, help us all out report bugs to:

http://bugreporter.apple.com

and report application (in)compatibilites to:

http://snowleopard.wikidot.com/

Save the screeching for the day your computer falls off your desk and breaks your foot. Until then, if you've got something useful to contribute, please do. Otherwise, well...

[bent42]

I think the screeching is a result of the fact that your statement "no software can be all things to all people all the time" flies in the face of the mentality Apple has tried to instill in it's user base. "Windows doesn't work." "Macs are superior, and by extension, Mac users are superior." All completely BS marketing, of course, but a lot of people buy into it.

[rick_beyers]

Ok. Here's the deal. Waited for something special from apple and got hugely disappointed again. Why one does this I don't know. Maybe I thought I could watch 3D movies 0n a 24 inch iMac, glasses included. Bottom line, I think I'll stick around a little longer to see what apple does in version 10.6.1 then make my decision to buy a new mac. Have a good one.

[ebpda9]

unless this is deja vu i do remember that cnet had an article about this when more details about the snow leopard came out. Why does this come as a surprise to so many people? It seems a bit fishy to me that apple claims that driver compatibility is an issue for the 64bit. When your have the entire control of the hardware, and when you have a limited number of devices supported it seems unacceptable not to have drivers.

[TheForestFloor]

All of Apple's drivers are 32/64bit clean. The problem is not with Apple's drivers... The problem is everyone else's. Printers, scanners, usb devices, data acquisition software, PC cards, etc all need to have 64bit drivers in order to work properly. Apple's driver framework, IOKit has many 'basic' drivers for most of these things, which is why nearly all ethernet cards, keyboards, mice memory sticks and cameras will continue to work. But for advanced features, extra buttons and functionality, a third party driver is required. Apple has had betas of SL out for over a year (since WWDC 2008), so driver and app writers have had plenty of time to get their code up to speed. However, writing and testing software is difficult, time consuming and expensive. Apple understands this, and has taken great pains to make sure that the user experience doesn't suffer too much while developers polish their code. They learned Microsoft's painful lessons with NT and Vista. Thankfully, Microsoft is also taking these lessons to heart with Windows 7 and beyond.

Good Software/OS development is an inclined plane, it moves (relatively smoothly) upwards. Large steps are jarring and often painful, so companies are trying to smooth out the bumps. They should be lauded, not jeered. Apple has a long tradition of successful transitions: 68k -> PPC, G3/4 -> G5, classic -> OSX, and now PPC -> Intel and I'm sure this one will be a success too.

Doubtless, people will complain about incompatibilities between 32/64 bit Windows 7, and 32/64 bit versions of Linux. Driver issues, installation issues, bugs and vulnerabilities are an inevitable consequence of software upgrades. All coders are affected; there's nothing 'fishy' about that.

[Vegaman_Dan]

@TheForestFloor:

"The problem is not with Apple's drivers... The problem is everyone else's. Printers, scanners, usb devices, data acquisition software, PC cards, etc all need to have 64bit drivers in order to work properly."

The irony is that this is one of the leading claims that Apple fans make to justify why Windows is such a failure in their viewpoint. I'm glad to see someone level headed enough to point out that the OS OEM cannot force third parties to produce good products / drivers on demand and that all you can do is fortify your own core OS to work with whatever you're given as best you can.

[wfolta]

Wow, what idiocy! I have a Mac right now with 24 GB of RAM in it, and it works just fine with 64-bit applications using 12 GB and more. THIS IS WITH PLAIN-OLD LEOPARD, PRE-SNOW-LEOPARD.

Snow Leopard will allow the OS itself to take advantage of > 4 GB of RAM. You can boot Snow Leopard in 32-bit mode and run 32-bit or 64-bit apps. You can boot Snow Leopard in 64-bit mode and still run 32-bit or 64-bit apps.

For the 10.6.0 release, it defaults to 32-bit for the OS. Which will run 32-bit or 64-bit applications just fine. Including some 32-bit Apple apps and some newly-64-bit Apple apps, and of course mixed third-party apps.

I would bet that 10.6.2 will default boot in 64-bit mode -- once third-party drivers are all updated -- on any machine capable of operating in 64-bit mode. Apple has seamlessly transitioned from PowerPC to Intel chips in a couple of smooth hops -- something no one else has done. Certainly not Microsoft. The Snow Leopard release is the second hop in the road to pure 64-bitness, and it will also be a smooth transition.

And all the PC fanboys are jealous.

[contentcreator--2008]

The problem that Apple has here is that they are (and have been) touting their 64-bit chops --- it is the lead item on the Snow Leopard page. Yet they are far far behind Microsoft on this one. Indeed Microsoft suffered through a rocky transition with drivers for Vista and for 64-bit, where 3rd party drivers were the major culprit, but they've done it.

Now Apple is here trying to have their cake and eat it too, claiming 64-bit is the big thing, but having to silently turn off their 64-bit kernel to avoid the same problems and maintain their air of moral superiority. It's tiresome. People have to just call BULLS**T on them. Apple and Microsoft both to do things good and horrifyingly bad, it's important to keep them straight.

[ikramerica--2008]

Your Mac Pro uses the RAM in a different way, though. It uses the RAM above 4GB as a replacement for paging in VM. In other words, it still sees "real" 4GB of RAM and then uses the rest for Virtual Memory, but VM on a ramdisk is lightning fast compared to VM on a hard drive. It's an expensive solution too, as it requires hardware to do it.

Snow Leopard in 64-bit actually allows your apps to use all that memory without the virtual memory paging overhead.

I have an Aluminum Intel Core 2 Duo iMac running Snow Leopard right now, and I've tried the 'hold 6+4' method at boot time, as well as the SUDO commands posted later on, and System Profiler still tells me that the 64-bit kernel and extensions = NO. what gives? I also punched in the command that DOES tell me that I have 'EFI64'... Is system profiler reporting incorrectly, and I can find out what mode my kernel is in, elsewhere?