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kaz7777 · Sep 12, 2003, 04:17 PM

Hi I have read in a couple threads, that Panther will not be a true 64-bit OS. Is this true? What does that mean? How is it not true, and does that mean its actually a 32-bit OS???

Hydra · Sep 12, 2003, 04:29 PM

Originally posted by kaz7777:
Hi I have read in a couple threads, that Panther will not be a true 64-bit OS. Is this true? What does that mean? How is it not true, and does that mean its actually a 32-bit OS???

No, Panther is not FULLY 64-bit. A Fully 64-bit os would not run on a 32-bit chip. Panther will have a bunch of things in it to take advantage of the 64-bit aspects of the G5 but still remain compatible for older 32-bit Macs too. It is a much more reasonable approach IMHO. Some things will gain nothing from a 64-bit implementation and others will a great deal. Why bother remaking the whole OS if it doesn't do anything for you? The PPC architecture has some major advantages over the x86 when it comes to 64-bit. The PPC was designed at the get go to have a migration to 64-bit - on the x86 it's a major overhaul and is not all that easy a transition.
I remember reading somewhere that the PPC started out as a 64-bit platform and eventually was converted to a 32-bit one with a future path to 64-bit instead (I could be wrong but it's moot anyway). When it comes to 64-bit OSX I think we are in excellent shape.

-Jerry C.

alien · Sep 12, 2003, 08:17 PM

kaz, I'm not sure whether you have any programming experience, but here's some kind of explanation.

Let's say I need to allocate some memory for some array of data elements I'm working on. When I do this, I get a "pointer" back from the OS, basically a memory address telling me where that array is.

Now, a 32bit pointer (4 bytes) can only point to 2^32 = 4GB of data. It's possible for the programmer to deal with more than 4GB indirectly, but this can be inconvinient. (I haven't tried it myself so I can't say more.)

For 64bit architectures, a pointer is 8 bytes long, so now it can point to 2^64 = some incredible amount of data. Even if the machine has much less physical memory, it can be very useful (specially in scitech and databases) to deal with such pointers for virtual memory.

Here's the situation: both 10.2 and 10.3 will use 32bit addressing. To be "fully 64-bit" Apple would have to provide both 32 and 64 bit libraries with OS X, but this could take some time for them to accomplish. (They are of course aware what the developers in these fields want.)

There are other aspects of 64-bit processing that OS X already does, or will do under 10.3.

The G5 hardware itself is capable of both 32 and 64 bit processing, and I wouldn't be surpriced to see 64 bit Linux running on the G5 in not too long.

The situation is similar with Opteron/Athlon64, since Windows for that processor is still 32 bit. Windows 64, I think, will be out sometime early next year. And it could take some more time after that before 64bit apps are out.

Disclaimer: This is my understanding of these issues, only...

Catfish_Man · Sep 12, 2003, 10:08 PM

Originally posted by alien:
kaz, I'm not sure whether you have any programming experience, but here's some kind of explanation.

Let's say I need to allocate some memory for some array of data elements I'm working on. When I do this, I get a "pointer" back from the OS, basically a memory address telling me where that array is.

Now, a 32bit pointer (4 bytes) can only point to 2^32 = 4GB of data. It's possible for the programmer to deal with more than 4GB indirectly, but this can be inconvinient. (I haven't tried it myself so I can't say more.)

For 64bit architectures, a pointer is 8 bytes long, so now it can point to 2^64 = some incredible amount of data. Even if the machine has much less physical memory, it can be very useful (specially in scitech and databases) to deal with such pointers for virtual memory.

Here's the situation: both 10.2 and 10.3 will use 32bit addressing. To be "fully 64-bit" Apple would have to provide both 32 and 64 bit libraries with OS X, but this could take some time for them to accomplish. (They are of course aware what the developers in these fields want.)

There are other aspects of 64-bit processing that OS X already does, or will do under 10.3.

The G5 hardware itself is capable of both 32 and 64 bit processing, and I wouldn't be surpriced to see 64 bit Linux running on the G5 in not too long.

The situation is similar with Opteron/Athlon64, since Windows for that processor is still 32 bit. Windows 64, I think, will be out sometime early next year. And it could take some more time after that before 64bit apps are out.

Disclaimer: This is my understanding of these issues, only...

Very close. 10.3 allows apps to address more than 4GB of memory though, and to use 64 bit integers. I suppose by "not fully 64 bit" people mean there are places where the OS itself could use 64 bit pointers or integers and doesn't. Seems like a bit of a stretch to me.

Hydra · Sep 12, 2003, 10:15 PM

Originally posted by Catfish_Man:
I suppose by "not fully 64 bit" people mean there are places where the OS itself could use 64 bit pointers or integers and doesn't. Seems like a bit of a stretch to me.

Well said.

-Jerry C.

lacrymology · Sep 12, 2003, 10:28 PM

The G5 is not a PPC... Apple just calls it that.

-m

Originally posted by Hydra:
No, Panther is not FULLY 64-bit. A Fully 64-bit os would not run on a 32-bit chip. Panther will have a bunch of things in it to take advantage of the 64-bit aspects of the G5 but still remain compatible for older 32-bit Macs too. It is a much more reasonable approach IMHO. Some things will gain nothing from a 64-bit implementation and others will a great deal. Why bother remaking the whole OS if it doesn't do anything for you? The PPC architecture has some major advantages over the x86 when it comes to 64-bit. The PPC was designed at the get go to have a migration to 64-bit - on the x86 it's a major overhaul and is not all that easy a transition.
I remember reading somewhere that the PPC started out as a 64-bit platform and eventually was converted to a 32-bit one with a future path to 64-bit instead (I could be wrong but it's moot anyway). When it comes to 64-bit OSX I think we are in excellent shape.

-Jerry C.

Hydra · Sep 13, 2003, 01:10 AM

Originally posted by lacrymology:
The G5 is not a PPC... Apple just calls it that.

-m

I'm not sure what your saying. The G5 is a PPC970 manufactured by IBM. Doesn't get more PPC than that. IBM even refers to it as a G5 when used in a Mac when looking in IBM's own documentation.

-Jerry C.

:XI: · Sep 13, 2003, 04:58 PM

Originally posted by lacrymology:
The G5 is not a PPC... Apple just calls it that.

-m

Originally posted by Hydra:
I'm not sure what your saying. The G5 is a PPC970 manufactured by IBM. Doesn't get more PPC than that. IBM even refers to it as a G5 when used in a Mac when looking in IBM's own documentation.

-Jerry C.

The IBM PowerPC 970 is a Fifth Generation PowerPC (G5). PowerPC is a subset of IBMs Power Architecture. Power was (I think) designed as a 64bit chip that could run in a 32bit mode. The 970 is based on the Power4.