Not being a hardware engineer, this is the first time that I heard that the PowerPC chip that was used in the 360 and Apples was based in anyway off technology that was the basis for Cell and paid for by Sony's R&D.
I was under the impression they were completely different architectures and for some reason I had though that the PowerPC architecture was around in Apples before the 360 was even in development.
Well certainly you must have heard before the similarities between the PS3 PPE and the XeCPU cores; it's been oft discussed around here. Now to square away with the obvious firewalling that should have been in place, the previous assumptions were that each respective team simply drew from the same original R&D project at IBM as the basis of their PPE designs. I forget the name of it, but it was of a high-speed prototype from 2000 or somesuch.
Apple chips, the 970, G4s/G5s... none of those are related to what we see in these consoles, these designs are based on a different branch.
Now so the question is whether both teams
did draw from the same original R&D project, or whether the PS3 team drew from it, and then the 360 team derived from what the PS3 guys were doing.
So, I'm a bit confused. Is the Cell just an 'extension' of the PowerPC chip? Adding the SPE's on top of the basic design?
The Cell chip is deterministic behavior, individual SPE processors, high-throuput, and the EIB slaved to a Power PC core. That's sort of what you said yourself, but I'm changing the emphasis to reflect what the chip is about. They could've done Cell without the PPE core at all for instance; could just as easily have had a different controlling architecture there, or none at all if design had shifted. I think the authors of this book though were closely linked to said PPE project, given the emphasis.
I'm also under the impression that the entire Cell processor's design (purpose/function) has been completely scrapped and essentially, the entire cost of developing the chip is a waste for all those involved when the development of other chips (core i7 for example), have vastly out performed anything the Cell processor was supposed to do. Especially considering the entire 'distributed computing' model has gone out the window which was supposed to be the key component of the chip.
Not at all! Has the Cell become a
commercial success? Certainly not, and the whole consumer electronics/Cell scene I hear the wind blowing period (though Toshiba will
finally show something in 2009 it seems). But from a design perspective I would consider it a qualified success (though I guess it depends on your design goals). The chip is even today still a leader in several of the areas in which it competes - basically against GPGPU in the cost/performance HPC space. In those areas - signal processing, cryptology, physics, etc - I would still rate the Cell more highly than the i7, especially from an architectural perspective as you get near linear scaling with additional nodes.
It's hard to know what place the Cell architecture will ultimately be given in the history books, and whether the architecture will evolve after this generation or be retired/supplanted, but it has earned some important "firsts" in the industry either way. Above all, I think the design
philosophies of its creators have been fully vindicated given the current arc of computing. Even if it dies after this gen, I think it'll always have been a case of certain 'near misses' - like should they have just gone cache instead? - but at least for some folk, I think it will always endure as a pioneer that had many novel things to bring to the table.
For IBM especially I believe, even if they change their arc significantly, I think they truly lucked out having Sony/Toshiba convince them to go this route, as it gave them a credible commodity chip with which to address the areas I listed above. They find themselves in a very advantageous position now infrastructure/SDK-wise relative to where they might otherwise have been in this new era that would have seen GPGPU ascendant and Larrabee on the horizon regardless of whether they were a player in that field or not. It's just too bad for Sony, Toshiba, and the Cell itself that that PPE was the PPC core that went into the chip, as truly it is holding back its appeal.
