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View Full Version : IBM970 vs G4 - software troubles ahead?


thies
Jan 17, 2003, 06:48 PM
I guess it's safe to assume that the IBM chip will make it's way into Macs sooner or later. What I am concerned about is: how different are they design wise? From what I heard I'd bet they are not similar enough for code to run on both unchanged. So, what is going to happen if this assumption of mine is true - how long will Apple support the G4 with software and how is the 3rd party software situation going to be? New versions of software only being released for the new architecture but not the old one anymore? Is it in that light, while not knowing what is going to happen at all a wise decision to buy a new Mac now which I'd use for a few years to come with the fear that I won't get updates for a lot if not most of the applications I use in a year from now as they are only being released for the new architecture?
Any comments or rumours in that regard floating around? :confused:

vniow
Jan 17, 2003, 07:07 PM
I don't think there'll be any trouble running your existing apps on a 970 system, they're both PPC after all and while the 970 is 64-bit vs the G4's 32-bit, it's backwards compatible so all your current stuff will still run on it.

Remus
Jan 17, 2003, 07:09 PM
From what I understand the 970 is based on the PPC chips so it should only have to be recompiled at most to run on the new chip. I am sure that it is backwards compatible.

thies
Jan 17, 2003, 07:17 PM
I am not concerned about BACKWARDS compatibility as I won't buy a IBM970. My concern is that once the cpu is released applications will be compiled just for it and not the G4 anymore which would render me purchasing a mac now completely useless as I won't be able to run any new apps on it.

Sun Baked
Jan 17, 2003, 07:17 PM
There's a bit of info on the future processors and implications in this thread, just go ahead and browse the 1200+ posts (the 970 info is in there, I just don't know where)

http://arstechnica.infopop.net/OpenTopic/page?a=tpc&s=50009562&f=8300945231&m=3470943335

vniow
Jan 17, 2003, 07:26 PM
Originally posted by thies
I am not concerned about BACKWARDS compatibility as I won't buy a IBM970. My concern is that once the cpu is released applications will be compiled just for it and not the G4 anymore which would render me purchasing a mac now completely useless as I won't be able to run any new apps on it.

The 970 is a PPC chip as well as the G4, there is no need to recompile them for either chip, they both carry the same instruction set.

thies
Jan 17, 2003, 07:29 PM
"The 970 is a PPC chip as well as the G4, there is no need to recompile them for either chip, they both carry the same instruction set."

which is nothing I heard as a definitive statement yet. usually the difference between 32bit and 64bit is big enough for there to be no binary compatibility.

vniow
Jan 17, 2003, 07:44 PM
Originally posted by thies
which is nothing I heard as a definitive statement yet. usually the difference between 32bit and 64bit is big enough for there to be no binary compatibility.

When the 970 comes out, it will run the same software that the current crop of G3s and G4s run. There will be no recompilation neccecary.
If an OSX app is written with a 970 Mac, it will be backwards compatible with the current linup and any other PPC computer that runs OSX. There is nothing to be worried about here. If the 970 was an x86 chip then we'd have a bit of a problem, but it's not.

The only incompatibility that you will ever see between the G4 and the 970 will be apps written for a 64-bit version of OSX which will only run on a 64-bit CPU (970) but we won't see a 64-bit version of OSX for awhile.

Catfish_Man
Jan 17, 2003, 07:51 PM
Obviously, people here don't understand instruction sets. All PowerPC chips run PowerPC code. PowerPC chips that implement PowerPC64 can ALSO run PowerPC64 code. The non-compatible chips people are thinking of are probably the Intel Itanium series chips (which have an utterly different architecture from the Pentiums, so of course it doesn't run the same code). The only other 64 bit transition is also 100% backwards compatible. The only possible problem is 64 bit only software not running on G3s and G4s, and that can be gotten around very easily using OSX bundles (similar to Altivec and non-Altivec code now, since Altivec code won't run on a G3). Hopefully that clears up both confusions going on.

Telomar
Jan 17, 2003, 07:58 PM
It'd be fine. There will certainly be apps that are optimised for a 64 bit environment and will run significantly better on a PPC970 (we're talking high end apps here) than a G4 but I'd be a touch surprised if there is anything that breaks compatibility. If you bought now you'd be safe.

Just to expand a touch what I expect Apple will do have it so most programs get compiled so that on launch they check the processor then they use code/libraries that are appropriate.

yosoyjay
Jan 17, 2003, 08:50 PM
I nearly shot myself after reading some of the other posts about how everything would have to be recompiled blah blah blah. I think you sucessfully ended this thread. Thanks!

nuckinfutz
Jan 18, 2003, 03:13 PM
The 970 is a PPC chip as well as the G4, there is no need to recompile them for either chip, they both carry the same instruction set.

Actually developers would want to recompile to take advantage of the superior features of the PPC970. It handles 8 instructions with 5 Dispatch. You can easily tweak your software to take advantage. Remember however that Libraries and other binaries are encapsulated in "Packages" and "Bundles" for OSX so it's easy for a developer to ship a "Fat Binary" of sorts for their apps with one for PPC75xx and one for PPC970

which is nothing I heard as a definitive statement yet. usually the difference between 32bit and 64bit is big enough for there to be no binary compatibility.

Why are you assuming your apps are going to be updated to 64bit anyways. Unless your running Databases and other huge number crunching apps plan on the basic apps staying at 32bit for some time. 64 bit doesn't necessarily give you more speed but it allows you to address much more memory.


The PPC970 is the same ISA no matter how easy it may feel to trump up concerns Software as Telomar eloquently pointed out, is easy retrofitted.

marapple
Jan 19, 2003, 06:52 AM
Let me first get out of the way that I know very little about processor architecture and the like, but I nonetheless would appreciate it if someone would clear up a few questions I have about Apple's current processors and a possible switch to IBM's 970. First, on Apple's website they refer to the G4 "Velocity Engine" as being able to process 128-bit chunks of data, but here on this discussion thread the consensus seems to be that the G4 has 32-bit architecture, what is the difference between the two? Second, is it pretty much assumed that Apple will adopt this new chip from IBM when it is available or is this just speculation? And lastly, how would this new IBM chip, with its 64-bit architecture, 1.4 Ghz - 1.8 Ghz processor speed, and so on compare to Intel's line of chips (e.g. their new 3 Ghz chip)?

Thanks

One more thing what is the bit-rate of Intelís chips?

benixau
Jan 19, 2003, 07:03 AM
the g4 is 32bit. if i understand correctly, all the 128bit means is that the velocity engine has 4 pipes for data to go through between it and the processor.

also the 970 will stand up pretty well. why? cause at even 1.8Ghz it looks like it is in the race. and with apple saying that the mhz doesnt matter much .... really though, intel is slowing their upgrades down. moores law has been modified three times. from 9mnths to 12mnths to now i think it stands at 18mnths.

they are reaching the limit. intel has adopted HT technology because they are running out of options. their marketing spool will go like so very soon: get the power of two procs in one unit for the price of one unit.

apple goes get 4 units in a machine for a little more and get the usual apple benfits .... i dint need ot expand there.

we will win. if only because we keep buying apple products.