MacOS – How old are Macs that cannot run 64-bit applications

32-bit64-bithistorymacos

We're trying to decide how much effort to put into ensuring that our software works well in 32-bit mode. (It's scientific software that must handle large datasets, so ensuring that it works well does not only mean building universal binaries, but also designing around address-space limitations.)

Q: In what year were the last Macs sold that, out of the box, could not run 64-bit applications?

By "out of the box," I mean in the hands of naïve users that do not upgrade the OS, choose different kernels, or change the system configuration from the default in any significant way.

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EDIT: Based on the comments on the question and this answer, I think the link Mac OS X v10.6: Macs that use the 64-bit kernel is much more relevant.

Basically, only the mid 2010 Mac Pro, the early 2011 MacBook Pro and the mid 2011 iMac were booting by default on 64-bit mode with Snow Leopard. Since Lion (mid 2011) every new Mac is 64-bit only.

So to answer your question:

In what year were the last Macs that were not capable (without user tweaking) of running 64-bit software sold?

==> 2011

EDIT 2: As Vebjorn Ljosa mentioned in the comments, having the kernel run in 32-bit or 64-bit mode makes little difference for your binary, so you can probably assume that Macs sold after mid 2007 will run a 64-bit app (based on the data just below).

Mac mini:
- last 32-bit only processors: late 2006
- oldest 64-bit capable processors: mid 2007
iMac:
- last 32-bit only processors: early 2006
- oldest 64-bit capable processors: late 2006
Mac Pro:
- always been 64-bit capable
MacBook:
- last 32-bit only processors: early 2006
- oldest 64-bit capable processors: late 2006
MacBook Pro:
- last 32-bit only processors: early 2006
- oldest 64-bit capable processors: late 2006
MacBook Air:
- always been 64-bit capable

So it seems the last Mac to sell with a 32 bits only processor was the late 2006 Mac mini.

Related Solutions

MacOS – How to know the kernel extensions are 64-bit ready

As far as I know, System Profiler won't display information for any .kext's that are being loaded and are located somewhere else besides the /System/Library/Extensions/ folder.

To get comprehensive information about the kernel extensions which are currently loaded and in use on your Mac, you can use the kextstat command line tool.

Open up the Terminal application (in the /Applications/Utilities/ folder), type the following at the prompt, and then hit return:

 kextstat

You will get a large list of all the loaded kernel extensions. You'll primarily want to focus on the bundle identifiers of the loaded .kexts. (That's the backwards domain name string such as "com.apple...."). You should be able to eliminate the ones that include "com.apple", as those will be Apple's and should have a K64 version. Once you've gotten rid of those, you'll then need to go over the remaining ones to make sure they are built as universal K32+K64 versions, or whether you may need to make sure you have the latest updates.

For example, after eliminating all the Apple kexts on the output I get, I have the following kexts listed. Since I switched to K64 a year or so ago, all of these are in order so everything is fine.

MacPro:~ mdouma46$ kextstat
Index Refs Address          Size   Wired  Name (Version) <Linked Against>
73  0 0xffffff7f8111a000 0x8000 0x8000  com.AmbrosiaSW.AudioSupport (3.2) <72 5 4 3 1>
81  0 0xffffff7f811bf000 0x9000 0x9000  jp.plentycom.driver.SteerMouse (4.0.2) <55 29 24 5 4 3>
105 0 0xffffff7f81499000 0x5000 0x5000  com.Cycling74.driver.Soundflower (1.5.2) <72 5 4 3>
115 0 0xffffff7f814bf000 0xd1000 0xd1000 com.vmware.kext.vmx86 (3.1.2) <7 5 4 3 1>
116 0 0xffffff7f81590000 0xc000 0xc000   com.vmware.kext.vmci (3.1.2) <5 4 3 1>
117 0 0xffffff7f8159c000 0x7000 0x7000  com.vmware.kext.vmioplug (3.1.2) <29 24 5 4 3 1>
118 0 0xffffff7f815a3000 0xa000 0xa000  com.vmware.kext.vmnet (3.1.2) <5 4 3 1>
119 0 0xffffff7f815ad000 0x2000 0x2000  com.nvidia.CUDA (1.1.0) <4 1>

MacOS – How to check whether the Intel-based Mac is 32-bit or 64-bit

To tell if you are running the 32-bit or 64-bit kernel (which matters for some device drivers), launch System Profiler and click on the Software heading in the Contents section.

The line 64-bit Kernel and Extensions will say Yes if you are running the 64-bit kernel and No if you are running the 32-bit kernel.

Note: Mac OS X 10.6 Snow Leopard is the last release that a 32-bit Intel Mac can run, Mac OS X 10.7 Lion and up are, by default, 64-bit. Additionally, System Profiler was renamed to System Information in OS X 10.7.

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Related Solutions

MacOS – How to know the kernel extensions are 64-bit ready

MacOS – How to check whether the Intel-based Mac is 32-bit or 64-bit

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