Is OS X 64-bit clean?

Discussion in 'Mac Apps and Mac App Store' started by MacManiac1224, Oct 10, 2002.

  1. MacManiac1224 macrumors regular

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    #1
    Is OS X 64-bit clean? If the Power4 chip by IBM debut's in the Powermac in the future, can OS X be recompiled easily enough to run on it? Will there be a lot of work for Apple's programmers if they want to change OS X and all it's iApps into 64-bit apps?
     
  2. Chaszmyr macrumors 601

    Chaszmyr

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    #2
    Its my understanding that all UNIX based operating systems are fairly easily compiled if the person knows what they are doing. If you recall the first time OSX was recompiled to run on X86 it was done by one person, and the Marklar project has less than a dozen people on it. If its that easy to run on X86, it should be just about that easy to run on 64 bit
     
  3. Billicus macrumors 6502a

    Billicus

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    #3
    Yes, but the x86 is also a 32 bit processor. Modifying OS X to run on a 64 bit processor would change how the OS processes information for the processor. I would say that that is easier said than done. :) :D :p
     
  4. madamimadam macrumors 65816

    madamimadam

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    #4
    The answer is no, I believe

    It will run because of the fact that the processor is backwards compatible, though

    I know M$ has a 64-bit beast in the works... most likely since Intel does not want to go 32/64 only 64. Whether it is another patch like M$ is known for or a full blown 64-bit machine... I don't know.
     
  5. benixau macrumors 65816

    benixau

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    #5
    OSX on X86

    Wher can i get this wonder, or find out how to do it. If i could get the PC in my house to run OSX then maybe it would work. Now there is something, A PC that would work with an OS from a big copmany, never heard of it you know .....
     
  6. vniow macrumors G4

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    #6

    They already have it.

    Windows XP 64-bit Edition
     
  7. madamimadam macrumors 65816

    madamimadam

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    #7
    So, it is a full blown 64-bit system or a 64-bit patch?
     
  8. vniow macrumors G4

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    #8
    I'm pretty sure it's full-blown 64-bit.
    I don't think it would be a good idea or even possible with good stability to 'patch' an OS to run at 64 bits, it makes more sense to develop both at the same time.:)
     
  9. madamimadam macrumors 65816

    madamimadam

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    #9
    True, but you might remember their first go at a 32-bit OS
     
  10. nixd2001 macrumors regular

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    #10
    Something worth clarifying in this thread is what exactly is meant by "64-bit clean". I'll give you my definition and then my understanding of what may or may not meet this definition. Others may disagree, but at least it will be possible to be more precise about the disagreement (which might appear a little revolutionary to some :eek:)

    First, forget about binaries, object code, compiled code, assembler, etc, for a minute and consider just source code. At this level, the question is really:

    Can the size of an address (pointer type, or void* in C) as implemented by the compiler be changed from 32 bits to 64 bits, the source code recompiled and it still continue to behave as expected?

    As far as I can tell, either xnu is already in such a state or a small number of updates to some key header files will achieve this. There may be some minor changes deep down in the kernel where the actual memory management takes place, but this is only an issue for Apple and everyone else can forget about having to do anything here - similar changes are often required whatever new CPU is to be supported.

    Then there is the question of the applications and core libraries (Core Foundation, Cocoa, etc). These appear to use a suitable level of abstraction such that, with any necessary system header file changes (again, something Apple would do once), it is possible to write 64 bit clean code. This doesn't guarantee that any individual programmer has actually done their job to a sensible quality level, but at least the ability to do so is not hindered by the environment.

    So next we should ask whether all of the Mac OS X applications, etc, from Apple actually are 64 bit clean. Unfortunately, we simply don't have enough information to answer this without actually trying it. There is good reason to expect 64 bit cleanliness to apply, but it only takes 1 mistake in 10s of millions of lines of code to make this assumption false. So the best we can really say here is probably.

    What about third party applications? Again, the best answer we can give is also probably, although it is likely that the probablity is lower. This is based on the guess that Apple have known about potential moves to 64 bits for longer and have had more incentive to go the extra mile to ensure 64 bit clean code.

    To finish off, let's return to 64 bit clean and object code. There is no really use definition here of what 64 bit clean might mean - in that the size of memory pointers was committed to at compilation time and hence it's too late to change things. So the issue that's relevant here is whether 32 bit clean applications can be run on a 64 bit processor with a 64 bit clean OS and applications without translation. Again, we don't have definitive information. It is reasonable to guess that they will work though. In order for them to work, the processor need to support both 32 bit and 64 bit variants of any instruction whose data size varies - this mainly being pointer/memory operations. That this can be done has been illustrated for many years by the Sparc family (as pointed out in a recent post somewhere near this thread), and also as intended to be the case with AMD's Clawhammer (or whatever its called). There is every indication that IBM (let's assume its IBM supplying us with a design for a 64 bit PPC processor for now) is both aware of the sense producing such a design, capable of producing such a design and having the intention of producing such a design. So it is probable that 32 bit applications will run without translation (and hence run at "native speed") on a 64 bit PPC.

    <diatribe end=true>

    Does this help anyone?
     
  11. DaveGee macrumors 6502a

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    #11
    Everyone here knows that moving a processor from 32bit to 64bit doesn't make it any faster right? It'll allow an OS and/or program to address more memory yes... but faster no... not in 99.9% of the cases.

    That being said...

    NeXTStep / OpenStep code was running on 64 bit hardware (I think). Mach runs on 64 bit hardware. BSD runs on 64 bit hardware. I think even Rhapsody ran on 64 bit CPUs. Apple knew 64 bit was the next step for many years. The PPC roadmap even said so.

    That pretty much covers the OS side of things... as for 3rd party apps... Well as someone else already stated the new CPU from IBM will run 32 bit apps just fine and with no modifaction needed. Developers can choose to move to 64 bit on an 'as needed' basis (most Apps will not see any real benefit to 64 bit - unless they are really memory starved)

    Given all that.. I really don't think we need to worry about X and any new CPU that might be on it's way. ;) If that's what this is all about about... If not then 'nevermind'. :D

    Dave
     
  12. bousozoku Moderator emeritus

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    #12
    Re: OSX on X86

    If that's your goal, why don't you buy the newly unbundled Solaris for x86 for $99? http://www.sun.com/
     
  13. MisterMe macrumors G4

    MisterMe

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    #13
    For those cryinng about how poorly our outdated Mac G4s are performing, by all means read this document. M$ claims that Windows XP 64-bit Edition can reach 6.4 Gflops on an 800 MHz Itanium. That is nice, no doubt about it. However, Apple claims that the dual 1.25 G4 can do 18.3 Gflops.
     
  14. madamimadam macrumors 65816

    madamimadam

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    #14
    One must admit, though, that the Itanium is not so much about floating point operations but about speeding up processes that are chocked by the 32-bit nature of other processors.

    Itanium is not supposed to make email and word faster ect.
     
  15. MisterMe macrumors G4

    MisterMe

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    #15
    Oh, contraire. Microsoft is tauting the floating-point performance in the Introduction of the referenced document. The point is reiterated two pages later in a section entitled Floating-Point.

    You confuse what is with what is supposed to be. Intel partnered with HP to develop IA-64 as a replacement for IA-32, as well as HP-PA. The fact that they have been unsuccessful the better part of a decade and several $billion later not withstanding.
     
  16. MacCoaster macrumors 6502a

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    #16
    Since when the M68k processors and x86 back then were 64 bit? No. They were 32 bit.
    Right... and it ever hits 18.3 gigaflops? Nope. That's theoretical peak and is very controversial because of this thread.

    Itanium is way faster than a PowerPC G4. Trust me.
     
  17. madamimadam macrumors 65816

    madamimadam

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    #17
    I think you misunderstand where I am coming from. You have to compare Apples to Apples, so to speak.

    What they want the Itanium to be and what it is can be 2 totally different things but at the moment it is working just fine for them in the sense that they can charge so much for it because it has no worthwhile competition IN ITS FIELD. If it was currently being produced to do the same tasks as the G4 then it would be MORE correct to compare the 2 figures but even then I would debate that it would be not be a good guide of overall performance.
     
  18. Sherman macrumors regular

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    #18
    Another point is that, oh, what speeds are the Power4's at? 2Ghz? something around there?

    Yea.

    Reason apple is taking so long with their new lineups: Trying to design a new motherboard for the Power4 and to add Bluetooth.

    MacWorld SF should be a good show.
     
  19. nixd2001 macrumors regular

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    #19
    According to a recent post on one of the threads here, Power4 is about to hit 1GHz. But don't get so obsessed with a basic clock rate. Think about how many instructions per second it can manage and how much data/code it can move between memory and the processor.
     
  20. peter2002 macrumors 6502

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    #20
    The key is optimatization.

    It would be easy to recompile, but the key is optimazation for 64 bit data structures. You would see a substantial increase in performance for 3D graphic apps, video games, DSP audio apps. Database programs that use large databases in excess of 4GB are the kinds of apps that benefit best from 64 bit technology. Other apps would see little, if any benefit. The reason is that 32 bit processors can recognize more than 4GB of memory directly, without bank switching.

    Obvisouly, this requires coding by hand to optimize an app for a particular 64 processor. I wouldn't expect much until 2005 because it will that long until desktops with more than 4GB of main memory. And it will take that long to work out the bugs in the software and OS.

    Right now, large corporate servers that run on Sun Solaris and IBM AIX benefit most from 64-bit OS and software..

    Peter :)
     
  21. MacCoaster macrumors 6502a

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    #21
    I thought 1.3GHz Power4s were already out. Hmm, you might be right.
    Proof? You ever see the price for the POWER4s? They're ****ing expensive. IMHO, POWER4 will never get in Macs. I'd be happy to be wrong on that, but realistically POWER4 is way out of league.

    Maybe IBM's new PowerPC at the Microprocessor forum.
     
  22. beatle888 macrumors 68000

    beatle888

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    #22
    " Proof? You ever see the price for the POWER4s? They're ****ing expensive. IMHO, POWER4 will never get in Macs. I'd be happy to be wrong on that, but realistically POWER4 is way out of league."

    but have you seen how close the intel P4
    came to the POWER4? If the POWER4 is so
    far out of apples league then why does the
    Intel P4 come so close the the POWER4?
    its in a post on the main page on the side.....wait i'll get the link.

    here check out the results
    MacRumors Post on Top Processor Results
     
  23. nixd2001 macrumors regular

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    #23
    I was uncertain and went digging. I mis-remembered a quote from Telomar:

    So I didn't actually have a speed rating - just a fab rating. My mistake.
     
  24. madamimadam macrumors 65816

    madamimadam

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    #24
    To be truthful, I think that is just like saying that the Itanium is way out of the league of desktop machines.

    Sure, at the moment it is and at the moment it is "****ing expensive" but by the time they expected to be implimented they will be the right cost.
     
  25. MacCoaster macrumors 6502a

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    #25
    Right. Exactly what I'm saying. I never said Itanium was desktop.

    Leave POWER4/Itanium where it is now and push it further for obvious reasons. Push desktop PowerPC/x86 further. When POWER4 and Itanium are a bit "dated," they might be powering our desktops at a much faster MHz ratings for each than right now. It's a matter of time. But in the next year or two, no way POWER4/Itanium is for desktop in Macs/consumer PCs.
     

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