Linked by moondevil on Wed 11th Jul 2012 22:49 UTC
Mac OS X Ars Technica is reporting that certain 64bit Mac models won't be able to run Mountain Lion. The problem is the graphic card drivers; these are still 32bit, and Apple is unwilling to update them to 64bit. A 64bit kernel can't load 32bit drivers, so that's that. Apple has a list of supported models on their Mountain Lion upgrade page, so you can easily check if your computer is capable of running Mountain Lion.
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RE[3]: No biggie
by Neolander on Thu 12th Jul 2012 13:13 UTC in reply to "RE[2]: No biggie"
Neolander
Member since:
2010-03-08

Well, it can be considered a secret, since what Apple calls "EFI" only remotely complies with the EFI and UEFI specs and keeps doing weird undocumented stuff (such as overwriting kernels after boot) all the time.

Here are some examples :
http://mjg59.livejournal.com/132477.html
http://mjg59.dreamwidth.org/12037.html

Reply Parent Score: 5

RE[4]: No biggie
by Alfman on Thu 12th Jul 2012 14:41 in reply to "RE[3]: No biggie"
Alfman Member since:
2011-01-28

Neolander,

Your links were a good read. The second one about the MAC boot process was eye-opening, wow are there a lot of dependencies. I'm not sure why apple would stray from a vanilla EFI implementation.

One parenthesised comment came up though and I think it's particularly relevant to a discussion of running 32/64bit OSes together.

"So then we have runtime services. EFI is, depending on how you want to look at it, either saner or much less sane than traditional BIOS access. The firmware gives you a bunch of function pointers and you then simply call them with native calling convention (this, incidentally, is why it's pretty much impossible to run a 32-bit OS on 64-bit EFI, or a 64-bit OS on a 64-bit system that happens to have 32-bit EFI)."

In theory, it shouldn't be too difficult to build a shim between 32bit and 64bit calling conventions. It might not be the most efficient solution, but I see no reason this shim couldn't be generated automatically from EFI function call prototypes.


A 64bit EFI should be able to handle zero padded 32bit OS pointers. The main question I have is whether the EFI data structures themselves change between 32bit and 64bit interfaces, because if they do then that rules out this simple trampoline approach.

Reply Parent Score: 4

RE[4]: No biggie
by lucas_maximus on Thu 12th Jul 2012 17:28 in reply to "RE[3]: No biggie"
lucas_maximus Member since:
2009-08-18

That is pretty shitty ... While I disagree with it I will have to point out when you buy an Apple Computer one buys it IMO for the integration between the hardware and the OS.

They support booting Windows because it is a common use case.

Reply Parent Score: 2

RE[5]: No biggie
by Neolander on Thu 12th Jul 2012 20:51 in reply to "RE[4]: No biggie"
Neolander Member since:
2010-03-08

And I agree that one can defend Apple's weird EFI implementation with this argument, to some extent. But it kind of gives fuel to the OP's point that alternative OS development on the Mac is not just unsupported, but actively discouraged.

Though as another interpretation, which is arguably equally valid, Apple might also use their nonstandard firmwares as a form of hardware DRM. After all, if Macs just used plain standard UEFI, with a well-documented and predictable behaviour, nothing would prevent the hackintosh community from just running OSX on a PC with a similar configuration. There are plenty of UEFI-compatible mobos out there nowadays...

Edited 2012-07-12 20:52 UTC

Reply Parent Score: 3

RE[4]: No biggie
by Delgarde on Fri 13th Jul 2012 00:13 in reply to "RE[3]: No biggie"
Delgarde Member since:
2008-08-19

Well, it can be considered a secret, since what Apple calls "EFI" only remotely complies with the EFI and UEFI specs and keeps doing weird undocumented stuff (such as overwriting kernels after boot) all the time.

Here are some examples :
http://mjg59.livejournal.com/132477.html
http://mjg59.dreamwidth.org/12037.html


To be fair, if you follow Matthew's posts, it's clear that *nobody* remotely complies with the standards.

Reply Parent Score: 2

RE[5]: No biggie
by phoudoin on Fri 13th Jul 2012 08:49 in reply to "RE[4]: No biggie"
phoudoin Member since:
2006-06-09

To be fair, if you follow Matthew's posts, it's clear that *nobody* remotely complies with the standards.


Indeed.

But only some manufacturers choose to keep private the non-standard-compliant/non disclosed features list. Many choose to publish it somehow in the hope that at least that may allow more people to find their product matching their needs.

Apple is not one of these later.
Worse, in they past they lock their hardware to only allow *their* operating system to run on it, now they lock softwares they don't want to run on their operating system.

I can see a pattern here.
Am I alone?

So, back to topic: either buy a new mac or stop rent your computing experience from Apple. You call.
But you were warning. Since long.

Reply Parent Score: 3

RE[5]: No biggie
by Neolander on Fri 13th Jul 2012 10:14 in reply to "RE[4]: No biggie"
Neolander Member since:
2010-03-08

My own impression from reading his blog was that most of current UEFI implementations have very serious bugs, but that no one but Apple has so far completely broken basic functionality such as OS detection ("You can can boot any EFI-compliant OS as long as it's Mac OS X") or the whole notion of boot-time services ("Here, do everything you want with that chunk of RAM, it's free for use after OS boot. The network chip may randomly decide to use it as a buffer from time to time though."). Seems like something done on purpose to me...

Edited 2012-07-13 10:20 UTC

Reply Parent Score: 3

RE[5]: No biggie
by zima on Mon 16th Jul 2012 01:27 in reply to "RE[4]: No biggie"
zima Member since:
2005-07-06

To be fair, if you follow Matthew's posts, it's clear that *nobody* remotely complies with the standards.

I suppose it is a spectrum though ...if you follow them, who's the worst / mildest offender?

Reply Parent Score: 2