forums.ps2dev.org

edepot · Joined: 09 Apr 2005 Posts: 111

The PS1 had a LSI 33Mhz CPU

The PS2 had a MIPSIII 300Mhz CPU and included this PS1 CPU for use as IO Processor in normal operating mode. The PS1 CPU took over during playstaion1 games.

The PS3 had a Cell and included the MIPSIII processor (and most likely the IO Processor, unless they copied over the PSP code)

The European PS3 most definitely have the IO Processor removed if it did exist before. This would explain having PS1 games emulated fully, and less PS2 games compatibility because some PS2 games may rely on strict timing of the hardware version of IO Processor.

Or maybe they removed all or some parts of the EE as well (like the mpeg unit or the
vector units). If they took the whole thing out it would also explain the low PS2 compatibility but good PS1 compatibility because they have good experience with the PSP's PS1 emulator.

In any case, there will definitely will be less compatibility with PS2 games because of
this hardware change. Most likely it will have 2 less CPU's (counting the PS1 chip) also.

The future firmware updates will most likely check the PS3 hardware and patch
accordingly, leaving hardware mode enabled for the first launch, and provide software
mode code for european launch PS3. This was noted in the news release (better
compatibility for earlier console compared to european ps3)

This means one thing... If you are interested in doing linux programming or XMB
homebrew development, it is a good idea to pick up the first launch PS3 before
everything gets changed to software. Then you have potentially 2 extra CPUs
to play with, and more value for your money. These classic PS3 will be worth more
too (with only a few million manufactured) when the future 100 million+ PS3s won't have the extra chips. Probably looking at one percent is first launch... and can be considered rare.

So this comes back to an interesting point. The first launch PS3 has (potentially)
11 CPUs.

1 PPE
8 SPE
1 PS2 CPU (EE)
1 PS1 CPU (IOP)

That is a lot of CPU's for coding on. Hope there are people there who can provide a way to access them. I think this is the only console with the most CPUs. Will most likely go down in history as a record holder.

disclaimer: The SPE may not be considered a CPU but they do execute code. As for the disabling of one of the SPE, it might be possible to reenable it via software. The other SPE used by the hypervisor can also be freed if the init code doesn't load it up with code and use it.

rapso · Joined: 28 Mar 2005 Posts: 147

I think the Cell is just one cpu, the SPUs are just cores, not seperated cpus. it's common to count it like that, as most commercial OS give their licenses dependant on the CPU count, and dual or quadcores are counted as single CPUs, as the X360 cpu (with 3cores) is just one.

In other case you could count the Shaderunits as CPUs as well, as they can run independant code and then you'd have 32 CPUs.

florinsasu · Joined: 15 Dec 2004 Posts: 47

I'm quite sure that the IOP was emulated in jap and us consoles. you can see the "beta" emulator in ps2 bioses (scph75k and 77k), under the name of DECKARD

probably they went one more step and removed the EE as well. i think the next firmware updates will have different ps2 kernels, for jap+usa and for europe (ie. with EE as chip or emulated)

Viper8896 · Joined: 26 Jan 2006 Posts: 110

Matrixdub · Joined: 13 May 2005 Posts: 60

It's redundant; incase one goes down.

Unless I'm mistaken.

FreeFighter · Joined: 14 Jan 2005 Posts: 43

As you said they did it to cut costs. But not like you say... They make wafers, where there's lots of cell chips on.

To reduce cost, the cell chips are allowed to have 1 SPE not working, it doesn't matter which one as long as there are 7 working SPEs. Even if all 8 are working, they'll only use 7. That way they throw away less chips.
They're also reducing costs by making the chips smaller, the smaller they get the more they can get on one wafer.

rapso · Joined: 28 Mar 2005 Posts: 147

ps2devman · Joined: 09 Oct 2006 Posts: 265

Nice tip!

That means, if you want to access SPE's you have to find out which one is damaged and avoid it. So there are software code that look for it and mark it as disabled...

Sony is selling damaged cells and advertise it as undamaged! Awesome!

Saotome · Joined: 03 Apr 2004 Posts: 182

rapso · Joined: 28 Mar 2005 Posts: 147

J.F. · Joined: 22 Feb 2004 Posts: 2906

A good example of how long they've been selling "defective" hardware - Motorola had three "versions" of the 68040 (the first chip they started doing that with):
68RC040 - CPU+MMU+FPU
68LC040 - CPU+MMU+broken FPU
68EC040 - CPU+broken MMU+broken FPU

They didn't even disable the faulty units... they simply told programmers that the units in those chips were "faulty" and would do "unspecified operations for an unspecified period of time" if you tried to use them.

On many, they worked well enough that people used them despite being faulty.

torakak · Joined: 29 Dec 2006 Posts: 4

ps2devman · Joined: 09 Oct 2006 Posts: 265

Hum... It's like discovering Santa Claus doesn't exist... Thanks for details.

About the missing EE+GS chipset...

I realized that a lots of people are pissed off because PS3 is not able to download a movie in background like xbox360 does while playing a game.

It's a shame. I'm pretty sure the extra EE processor could have handled a background download...

Well... it's something the future ps3dev will allow to do I bet... on non european, v1.32 or below, ps3's...

wich · Joined: 14 Feb 2007 Posts: 13

I don't think you need the EE to download a movie. Doesn't the hypervisor continue to run while running a game? I bet it could also run a process for a download, I would think it's more a matter of firmware than anything else. A simple download uses next to no resources on the processor.

ralferoo · Joined: 03 Mar 2007 Posts: 122

jockyw2001 · Joined: 29 Sep 2005 Posts: 339

Yeah, it's a damn shame. I already had planned to use it for idct and csc calcs.