IGN on XBox 360's backwards compatability

[GFLPraxis]

http://xbox360.ign.com/articles/639/639656p1.html

"Microsoft has) implemented compatibility purely through emulation (at the CPU level). It looks like emulation profiles for each game are going to be stored on the hard drive, and I imagine that a certain number will ship with the system. They already have the infrastructure to distribute more profiles via Live, and more and more can be made available online periodically."

...

So, it's a waiting game. And it's going to be a frustrating one. The first list of backward compatible games, we suspect, will be short. But as time passes, the list will grow to include many more favorites.

There's been a lot of debate about the XBox 360's backwards compatability and the meaning of "top selling titles", or whether it's fully backwards compatible, but this confirms it; my original theory about patches (Microsoft is using the term 'emulation profiles') was correct.

Microsoft had made some mention of preloaded "emulation profiles" but not enough to end the debate.

Basicly, the hard drive comes preloaded with some of these 'emulation profiles' so the XBox 360 can play some of the 'top selling' games. As time goes on you'll be able to download more off of XBox Live, making more and more games compatible, though if you don't have the XBox 360 hooked up to the internet, you're stuck.

[runninmac]

I dont know how I feel about that it could take a while to download if thyre huge. Anyone know how big they HD is gonning to be 20? 40? one of them seems right. They better not fill up the whole HD

[GFLPraxis]

I'd figure the patch would just be the binary, which is one of the smallest parts of an application.

If you have a Windows PC, find a game and right click on the .exe file and press properties. For example, Star Wars Battlefront's binary is 5 MB; the entire game on the other hand comes on 3 CD's and is several gigabytes.

So I'm sure you could fit hundreds of patches on a 20 GB hard drive. It's not the full game.

[Phat_Pat]

well at least they're trying.....

[Yvan256]

Who cares, anyway? Seriously?

Metroid and Zelda are gonna be on the Revolution.

[GFLPraxis]

I'll EVENTUALLY get a second console.

I'm leaning towards the PS3 because;

1) I liked the games lineup on the PS2 more than the XBox; Sony has some good stuff, like Ratchet and Clank, Jak, FF, and Kingdom Hearts.
2) By the time I buy it, there will have been price drops, and my sister works at Best Buy, so I'm not worrying about the up-front cost because I'll get it for less than anyone else would anyway.
3) Linux rules! It's always nice to have another PC.
4) Sony hasn't said anything about charging for online.

If it turns out that Sony is charging for online play too, and Microsoft picks up some better games, I may consider the XBox 360.

It's irrelevant for now; I'm buying a Revolution on launch day, and a second console in a year or two when decent games come out as I don't like EITHER of their launch titles.



Super Smash Bros Online. I will pwn you all!!!!111

[jared_kipe]

They won't be patching binaries, they are emulating x86 code. I suspect that especially on earlier titles, there can be one profile that runs many games. Games that make use of the same set of features, or similar graphics types.

[PharmD]

I don't understand why they can't make it backwards compatible like Sony did with the PS2, which basically had a PSone built in. Sony and Nintendo have it figured out.

[TheMonarch]

Originally Posted by PharmD

I don't understand why they can't make it backwards compatible like Sony did with the PS2, which basically had a PSone built in. Sony and Nintendo have it figured out.

$

[Xenious]

I just realized:

Apple switches to Intel, uses emulation to support older PowerPC binaries.
Microsoft switches to PowerPC (on Xbox 360), uses emulation to support older Xbox binaries.

<Emulate voice="Michael Dorn">
There is the theory of the Mobius. A twist in the fabric of space where time becomes a loop.
</Emulate>

hahaha

[kuyu]

I could personally care less about backwards compatibility. I never played a single PS1 game on the PS2, and I don't anticipate playing any xbox games on the 360. I guess I'm sort of a technology slut, nothing but the best intices me.

Plus with the Revolution and 360 and five or so games per console at launch, I don't see myself having any time for old games anyway (except for excitebike 64, of course). Which reminds me... Please nintendo, make excitebike revolution! Gyro-squeezable controls are perfect for a motorcycle game!!!

[rockthecasbah]

Originally Posted by Yvan256

Who cares, anyway? Seriously?

Metroid and Zelda are gonna be on the Revolution.

woo woo nintendo fanboys unite

[GFLPraxis]

Originally Posted by PharmD

I don't understand why they can't make it backwards compatible like Sony did with the PS2, which basically had a PSone built in. Sony and Nintendo have it figured out.

The Nintendo Revolution is NATIVELY backwards compatible. Both the GameCube and Revolution used PowerPC processors and ATi graphics cards.

PS3, I don't know how they're doing it.

But Microsoft has changed EVERY component in the system. With the PS2 and PS1 I think they were at least similar, they just included the PS1 processor. With the XBox 360 they'd need to include everything, the entire XBox processor, the entire XBox GPU, etc.

[GFLPraxis]

Originally Posted by kuyu

Please nintendo, make excitebike revolution! Gyro-squeezable controls are perfect for a motorcycle game!!!

I'm just saying, "Nintendo, make gyro-squeezable controls" Gah, too many rumors, so little time....

[gco212]

The problem isn't with emulating the Xbox's processor, that's easy. The problem is mostly with emulating the GPU, as the two architectures are very different and difficult change. And the reason Xbox can't be backwards compatible like PS3 and just include the chip is because it doesn't own the chip. The Xbox took a slightly changed processor and GPU from computers to use, but it wasn't given ownership of the designs. PS2, however, owns the designs so it is able to get the processors and GPU's at cost. Xbox, however, would have to buy them from Intel and nvidia.

[GFLPraxis]

Originally Posted by gco212

The problem isn't with emulating the Xbox's processor, that's easy. The problem is mostly with emulating the GPU, as the two architectures are very different and difficult change. And the reason Xbox can't be backwards compatible like PS3 and just include the chip is because it doesn't own the chip. The Xbox took a slightly changed processor and GPU from computers to use, but it wasn't given ownership of the designs. PS2, however, owns the designs so it is able to get the processors and GPU's at cost. Xbox, however, would have to buy them from Intel and nvidia.

Actually, the processor IS the problem. It's not easy at all. We all know the performance loss when a PowerPC processor emulates an x86. Well, this situation is even worse, because Microsoft has three slow PowerPC's instead of one fast one, and you cannot use three processors to emulate one. So right there, the XBox 360 can only use 1/3rd of its power to emulate the XBox. Add to that the lack of AltiVec and the fact that those processors don't even support out-of-order-execution (a hardware feature that the XBox DOES have, but the 360 does not), then emulation becomes REALLY DANG HARD.

[Abulia]

Originally Posted by GFLPraxis

Actually, the processor IS the problem. It's not easy at all. We all know the performance loss when a PowerPC processor emulates an x86. Well, this situation is even worse, because Microsoft has three slow PowerPC's instead of one fast one, and you cannot use three processors to emulate one. So right there, the XBox 360 can only use 1/3rd of its power to emulate the XBox. Add to that the lack of AltiVec and the fact that those processors don't even support out-of-order-execution (a hardware feature that the XBox DOES have, but the 360 does not), then emulation becomes REALLY DANG HARD.

Ah, excellent. More M$ speculation and "doom and gloom" predictions. According to my calendar, we're right on schedule.

Funny, Microsoft does software emulation on the Xbox and we're talking worse case scenario. ("You'll only be able to play Halo!") Apple does emulation via Rosetta and it's some master-stroke of brilliance. Yes, I realize they're not functionally the same, but conceptually (emulation) they are.

Shouldn't we get some firsthand reports on how the 360 plays these games before passing judgment? Oh, wait, that's crazy talk.

What's next? Nintendo charging for the previous library? The PS3 Killzone video being pre-rendered? Oh, wait…

Personally, it's not that big of deal, since I already own an Xbox. Plus, it's not very likely I'll be playing my old library once I have a 360, beyond some key titles. Joe Consumer may be different, however.

[Counterfit]

Originally Posted by GFLPraxis

Super Smash Bros Online. I will pwn you all!!!!111

I think you just sold me on the Revolution

[TheMonarch]

Originally Posted by GFLPraxis

Super Smash Bros Online. I will pwn you all!!!!111

Whenever it comes out....


PREPARE TO MEET YOUR DOOM!!!

[gco212]

Originally Posted by GFLPraxis

Actually, the processor IS the problem. It's not easy at all. We all know the performance loss when a PowerPC processor emulates an x86. Well, this situation is even worse, because Microsoft has three slow PowerPC's instead of one fast one, and you cannot use three processors to emulate one. So right there, the XBox 360 can only use 1/3rd of its power to emulate the XBox. Add to that the lack of AltiVec and the fact that those processors don't even support out-of-order-execution (a hardware feature that the XBox DOES have, but the 360 does not), then emulation becomes REALLY DANG HARD.

"Emulating the CPU isn't really a difficult task. They have three 3GHz cores, so emulating one 733MHz chip is pretty easy. The real bottlenecks in the emulation are GPU calls - calls made specifically by games to the nVIDIA hardware in a certain way. General GPU instructions are easy to convert - an instruction to draw a triangle in a certain way will be pretty generic. However, it's the odd cases, the proprietary routines, that will cause hassle."

[GFLPraxis]

Originally Posted by Don M.

Ah, excellent. More M$ speculation and "doom and gloom" predictions. According to my calendar, we're right on schedule.

Um, what? I don't see doom and gloom predictions, I explained why it was difficult and they have to write "emulation profiles" for individual games instead of making an all-purpose emulator like Rosetta.

[Eric5h5]

Originally Posted by gco212

"Emulating the CPU isn't really a difficult task. They have three 3GHz cores, so emulating one 733MHz chip is pretty easy.

Apples and oranges. You can't just compare the MHz values and get anything meaningful out of it, and you especially can't just multiply by 3 and get 3 times the performance. (Which I know quite well, as the owner of a dual G5. Nice, but not twice the speed.) As GFLPraxis said:

"It's not easy at all. We all know the performance loss when a PowerPC processor emulates an x86. Well, this situation is even worse, because Microsoft has three slow PowerPC's instead of one fast one, and you cannot use three processors to emulate one. "

I'm deducing, from what I've read, that one of these 3GHz chips is about as fast as a 1.5GHz G5 in general operations. For some things, it would be faster, but emulation counts as general operations. Try getting a 1.5GHz G5 to emulate a 733MHz PIII(ish) at full speed consistently...right.

--Eric

[GFLPraxis]

Originally Posted by Eric5h5

Apples and oranges. You can't just compare the MHz values and get anything meaningful out of it, and you especially can't just multiply by 3 and get 3 times the performance. (Which I know quite well, as the owner of a dual G5. Nice, but not twice the speed.) As GFLPraxis said:

"It's not easy at all. We all know the performance loss when a PowerPC processor emulates an x86. Well, this situation is even worse, because Microsoft has three slow PowerPC's instead of one fast one, and you cannot use three processors to emulate one. "

I'm deducing, from what I've read, that one of these 3GHz chips is about as fast as a 1.5GHz G5 in general operations. For some things, it would be faster, but emulation counts as general operations. Try getting a 1.5GHz G5 to emulate a 733MHz PIII(ish) at full speed consistently...right.

--Eric

Precisely.

My guess is thats why they're using these "emulation profiles". Since they can't write a general purpose emulator like Rosetta or VPC that'll work for everything, they just write "emulation profiles" for each game with a highly optimized emulator (either that, or a PowerPC binary, whichever Microsoft prefers) designed just for that game.

Voila, it works, except that you have to download this "emulation profile" for each game you have if its not already on the hard drive.

[crachoar]

Microsoft can't include the nVidia GPU on the board because nVidia charges them an outrageous amount of money per GPU - which is why they took a loss for the original Xbox.

This is why they have to do what they're doing now. The CPU 'issue' isn't really an issue. It's the GPU that is causing the problem.

[DeSnousa]

Originally Posted by GFLPraxis

The Nintendo Revolution is NATIVELY backwards compatible. Both the GameCube and Revolution used PowerPC processors and ATi graphics cards.

PS3, I don't know how they're doing it.

But Microsoft has changed EVERY component in the system. With the PS2 and PS1 I think they were at least similar, they just included the PS1 processor. With the XBox 360 they'd need to include everything, the entire XBox processor, the entire XBox GPU, etc.

I think it has to do with the cell processor in the PS3, which supports many platforms or something like that.