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Member since:2005-07-06
One running copy of AmigaOS4 would need only a fraction of the CPU time of one PPC core.
That's a given. It's about CPU-intensive applications. The Amiga platform doesn't have many developers to spare to try and rewrite those applications for the SPEs. The Xenon's symmetric architecture would provide a much more straightforward upgrade path, once AmigaOS gains multi-processor capability anyway.
There are hybrid 68k/PPC (also even x86) multi-CPU Amiga systems
But there's no special operating system support for them, right? The PPC or x86 just acts as a kind of coprocessor?
AmigaOS multi-threading support is planned for AmigaOS4.1
Are you sure they call it multi-threading?
Afaik multi-threading means the ability to split your application into (pseudo-)parallel threads. AmigaOS always supported that, it's just that its "threads" are called "tasks".
Member since:2005-07-10
> There are hybrid 68k/PPC (also even x86) multi-CPU Amiga systems
But there's no special operating system support for them, right? The PPC or x86 just acts as a kind of coprocessor?
That's correct. PPC and 68k apps run on this hardware platform perform poorly, because you need to add-on memory management (WarpUP or PowerUP) between those cpus. The performance is not optimal, because of task switching penalties when switching between AmigaOS and WarpUP/PowerUP operation.
AmigaOS4 turned this around by adopting the PPC as main CPU and emulating the 68k, handling all this inside the kernel, making performance much faster.
Thus the 68k is not functional on those PPC A1200/A4000's that run the AmigaOS4 prerelease.
Member since:2005-07-06
@ nimble
> But there's no special operating system support for
> them, right? The PPC or x86 just acts as a kind of
> coprocessor?
The x86 CPUs were mainly used to boot MSDOS/Windows, next to or inside AmigaOS at good speeds.
The PPC expansion boards were used to run PPC WarpOS (AmigaOS 3.9 default included PPC support OS by H&P) or PowerUP (Phase5) software. Actually WipeOut 2047 as shown within the video isn't an AmigaOS4 native game, but the PPC WarpOS version running inside a wrapper.
BTW, these PPC boards can in the future also be used to run AmigaOS4 on classic systems:
Old demonstration video:
Hardware specs: Amiga 1200 with Blizzard PPC accelerator card with the CPU clocked at 166 Mhz, 128 MB RAM and BlizzardVision (Permedia 2) graphics card.
http://intuitionbase.com/multimedia/OS4_BPPC.avi
> Are you sure they call it multi-threading?
Yes, the difference explained (AW thread from 2003):
http://amigaworld.net/modules/newbb/viewtopic.php?topic_id=1056&for...
Member since:
2005-07-06
@ nimble
> They'd be better off going for the Xenon with its
> three symmetric PPC cores.
One running copy of AmigaOS4 would need only a fraction of the CPU time of one PPC core. What you saw running in this video was on a G3 at 800 Mhz. The simplified PPC core planned as to be used for the PS3''s cell would be a lot faster and clocked at 3.2 Ghz (for specialized software there are 7 active Self-multitasking of SPEs also clocked at 3.2 Ghz each).
One reason why I believe the Cell to be much more interesting is that the Cell is going to be used in lots more decides than solely for the PS3, like in digital TVs, STBs, servers, etc.
Higher clocked versions are also planned and you can even use mutliple Cells within one system, as demonstrated on the Blade server which uses 2 Cells clocked at 2.4 Ghz and was demonstrated running Linux recently.
> (But does AmigaOS actually support multiple
> processors yet?)
There are hybrid 68k/PPC (also even x86) multi-CPU Amiga systems, but AmigaOS multi-threading support is planned for AmigaOS4.1.