Will your Mac boot 64-bit Snow Leopard by default? Not unless it's an Xserve

Will your Mac boot 64-bit Snow Leopard by default? Not unless it's an Xserve

Summary: If the current developer seed (build 10A432) of Snow Leopard is indeed the Golden Master version (as has been highly rumored) only Xserves will be able to boot into 64-bit version of Mac OS 10.6 by default.

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64-bitIf the current developer seed (build 10A432) of Snow Leopard is indeed the Golden Master version (as has been highly rumored) only Xserves will be able to boot into 64-bit version of Mac OS 10.6 by default. All other Mac users will have to hold down the "6" and "4" keys at boot to load the 64-bit kernel and kexts. Every time.

OS News reports that some Macs with 64-bit processors won't be able to load the 64-bit kernel because they have a 32-bit EFI. The seed notes explain which Macs can boot into a 64-bit kernel and drivers by default (Xserve), and which ones are only "capable" -- meaning you have to hold down the 6 and 4 keys at boot.

Here's the list:

64bit support in Snow Leopard.

Still not sure if your Mac has the 32 or 64-bit EFI? You can check your machine's it by entering the following command in Terminal:

ioreg -l -p IODeviceTree | grep firmware-abi
It will return either "EFI32" or "EFI64."

OS News notes that only Macs with a 64-bit EFI are able to boot the 64-bit Snow Leopard kernel and kexts; an artificial limitation imposed by Apple, even though a 32-bit EFI can boot a 64-bit kernel "just fine."

What's worse is that even if your MacBook (non-Pro) has a 64-bit EFI, it will only be able to boot the 32-bit version of Snow Leopard because of a limitation that Apple imposes on MacBooks. The biggest roadkill on Route 64 is the original Mac Pro (which was discontinued January 8, 2008) it won't be able to boot the 64-bit kernel and drivers either.

If you're worried about being stuck in the slow lane with a 32-bit EFI, there's hope. The Netkas blog has posted some workarounds for booting the x86_64 kernel on a 32-bit Mac. Also, keep in mind that it hasn't been confirmed that 10A432 is the GM version of Snow Leopard and Apple could change the limitations above any time via an EFI update.

Topics: Networking, Hardware, Processors

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  • Mac Mini returns EFI64

    I got my Mac Mini in April, so I think it's the latest or at least only 1 iteration behind. I ran your command and got EFI64 back. I've SuperDuper'd my system to an external drive so I'm ready to give it a try.

    Unless...

    Will all my apps install to a 64-bit system?
    wuulfgar
    • Good question.

      When I ran the command this is what it returned.
      | | "firmware-abi" = <"EFI64">
      This is from an early 2009 Unibody 2.66 GHz Macbook Pro. I think that
      Apple will fix the "issue" reported here. Remember the people in
      question, are reporting on a beta build.
      Rick_K
    • Kernel or Applications?

      The article refers to running a 64-bit kernel, not 64-bit applications.

      Apple's 32-bit kernel runs 64-bit applications today (with 64-bit
      virtual
      memory addressing).

      A 64-bit kernel requires 64-bit KEXTs, which aren't always available
      (yet). I suspect a greater number of Apple systems will support the
      64-bit kernel either by release or shortly after.

      It's not that big of an issue, blown up the lack of understanding of the
      Mac OS X architecture. It's something Apple should enable for as many
      boxes as possible.
      Richard Flude
      • So no impact?

        So there is no advantage to being able to run a
        64-bit kernel vs a 32-bit kernel?
        bmonsterman
        • Right, very little

          Running a 64-bit kernel can reduce the number of mode switches
          making it marginally faster, however can be slower on memory
          constrained systems.

          Performance is largely dictated by userland applications.
          Richard Flude
    • Yes you can install all your 32 bit apps. <NT>

      <NT>
      AdventTech67
    • another snow job from the authors above

      yeah my 2006 iMac lists 64 bit EFI too

      what a NON story

      32 bit app installs?
      I will say, with as much authority as the doofuses who authored this article:
      YES!
      gennx30
    • This is an artificial limitation imposed by Apple, most likely to ...

      ... reduce the support burden.

      Apple's thinking here is most likely some version of: "unless a user specifically needs 64-bit support, why boot said user into a 64-bit OS?"

      Because this is the first mainstream release of Apple's pure 64-bit OS, they're clearly going to want to reduce compatability issues for their users.

      Besides which, if a user has a machine with 4GB RAM or less, they are unlikely to see significant benefits by moving to a 64-bit OS.

      Windows, on the other hand, is in it's 3rd pure 64-bit desktop OS (XP64, Vista 64-bit and now Win7 x64) and has a more mature and tested 64-bit ecosystem.

      OSX' 64-bit support will catch up with Windows' eventually, but will do so slowly, and only as Apple's telemetry tells it that it's customers machines are fully capable and when its 64-bit compatability issues reduce to a comfortable level.
      de-void-21165590650301806002836337787023
  • This is SOOOO confusing!

    So some Macs are Vista Capable... um... I mean OS X Capable and some are OS X ready? And there are 2 versions of OS X? Which do I need? Is the XServe version better than the non XServe version? And that chart is too confusing. How do I know if I need to hold down the 6 and the 4 key when I boot up and when I need to hold down the 3 and the 2 key? I think I have a MacBook Pro but I'm not really sure. Aren't all Macs the same? Isn't that why Apple controls the hardware and the software?

    Sigh, why can't Apple just make this simple. I'm SOOOO confused.
    NonZealot
    • Keep it simple then

      "So some Macs are Vista Capable... um... I mean OS X Capable and
      some are OS X ready?"

      All intel macs are snow leopard ready.

      "And there are 2 versions of OS X?"

      Yes, server and desktop.

      "Which do I need?"

      If running a server use the server version, if a desktop use the
      desktop version.

      "Is the XServe version better than the non XServe version?"

      No, they're different.

      "Sigh, why can't Apple just make this simple. I'm SOOOO confused."

      Can't distinguish between a server and desktop?
      Richard Flude
      • Let me help !

        ""Sigh, why can't Apple just make this simple. I'm SOOOO confused."

        Can't distinguish between a server and desktop?"


        Oooh ! Oooh !

        I know the answer, Mr Car-Ter !

        The Xserves are the flat pizza box shaped computers that don't have
        optical drives !

        There, now, NZ. Does that help?
        Jkirk3279
        • @jkirk3279

          xserves have optical drives, cluster nodes don't.
          Axsimulate
          • @Axsimulate

            Stop clouding the issue with facts!
            WarhavenSC
          • LOL-NT

            nt
            mathcreative
    • Not Confusing

      First off all the 64-bit compatible Mac already run 64-bit programs
      already, in 64-bit.

      Right now you can open the Info Box for a program by
      command+clicking the application and unchecking the 32-bit box.

      I suspect that the premise of this article is based either on not having
      the final version of Snow Leopard, or lack of knowledge on the part of
      the author.
      yobtaf
    • The key to good humor or satire

      is that it be based somewhat in reality, and not just zealotry.
      frgough
    • Please don't feed the trolls.

      thank you
      Jason D. O'Grady
      • But he has a point, at least

        [i]OS News notes that only Macs with a 64-bit EFI are able to boot the 64-bit Snow Leopard kernel and kexts; an artificial limitation imposed by Apple, even though a 32-bit EFI can boot a 64-bit kernel ?just fine.?

        What?s worse is that even if your MacBook (non-Pro) has a 64-bit EFI, it will only be able to boot the 32-bit version of Snow Leopard because of a limitation that Apple imposes on MacBooks.[/i]

        Seriouslly, with all the dancing and finger pointing on Windows versions and what works/does not work and 2 separate versions (32/64), I guess Microsoft is not the only one that can have a finger pointed at them.

        Why does Apple feel the need to place artifical limitations on their hardware? The only reason I can see is that if you wish to utilize their 64 bit operating system, then you will need to purchase new hardware.

        And is it not hardware in which Apple makes their profit?
        GuidingLight
        • No...

          [i]"Why does Apple feel the need to place artifical limitations on their
          hardware? The only reason I can see is that if you wish to utilize their
          64 bit operating system, then you will need to purchase new
          hardware."[/i]

          Mac OS X Snow Leopard will run 64-bit applications (with 64-bit
          memory addressing) with [i]either[/i] the 32-bit or 64-bit kernel.

          If you're unsure if your computer is capable of running in full 64-bit
          mode, use the 32-bit one. It doesn't matter.

          This is a very smart way of transitioning to full 64-bit. This gives
          developers plenty of time to make 64-bit clean drivers for any 3rd
          party devices.

          End users can install any and all 64-bit software without sacrificing
          existing hardware support by switching to a 64-bit kernel.
          olePigeon
    • Confusion is understandable

      Here is a simple solution.
      1. There is only ONE version of OS X UNLESS you are running an XServe
      Machine. IF you don't know what an XServe machine, you aren't
      running one. (see this link: http://www.apple.com/xserve/)

      2. Regardless of what version of iMac/Mac Mini/MacBook/MacBook
      Pro you are running you can always run 32 Bit. 64 Bit allows for some
      speed related tricks similar to removing the restrictor plate in a
      NASCAR race car and allowing it to go as fast is it can possibly go.
      This is not quite a correct analogy, but it gets the point across that
      even with 'restrictions' your Mac is still speedy and very capable of
      running Snow Leopard.

      3. If you want to find out IF you CAN run in 64 Bit mode, SHOULD YOU
      WANT TO, follow the command at the end of the article and copy-
      and-paste it into a Terminal window and see if your result is 32 or 64.
      My older MacBook Pro is 32 but my newer iMac is 64 capable. Now,
      unless there is software out there to take advantage of this, it's not
      very useful to the average end user.
      Jonathan D Rowson