xBOX 360 BACKWARDS COMPATABILITY. THE REAL TRUTH?

evad_lhorg

On Tuesday we reported that Microsoft spokespeople had claimed that the Xbox 360 will be 'backwards compatible with some top-selling titles'. While at the time we speculated that this might mean that the device would use software emulation rather than embedded hardware, we've now got to the bottom of it.

Microsoft have explained that current Xbox games will simply be incompatible with the 360. The problem being, of course, that while the Xbox uses an Intel CPU and an nVidia graphics unit, the 360 comes equipped with an IBM processor and ATI GPU.

Xbox games will all theoretically be able to play on the next gen XBeast, but only if they are recompiled. Needless to say, unless you are some kind of 1337 hax0r, that's not the kind of procedure you're going to be able to carry out at home. We imagine that they are saying you'll be able to purchase the same old Xbox titles, but formatted instead to work on the 360. This explains why they said only 'top-selling' games - each title will have to be re-manufactured to run on the 360, and this will be driven by demand.

It's difficult to see what would induce people to buy games that they already own just to avoid the hassle of plugging their old 'box in again. The obvious solution to us would be some sort of exchange policy where people can trade in their old software for a 360 friendly-version.





from spong.com

Ciaran500

Spong are a shite news source TBH.

http://www.majornelson.com/2005/05/19/no-you-do-not-need-to-recompile-your-xbox-games/

jesus_thats_gre

http://www.gamespot.com/news/2005/05/20/news_6126204.html

RUMOR #2: The Xbox 360 won't be backward compatible after all.

Source: British industry news site Gamesindustry.biz.

The official story: See below.

What we heard: Microsoft carefully parsed its words about the Xbox 360's backward compatibility by saying it will be "backward-compatible with top-selling Xbox games." So when Gamesindustry.biz published an article revealing the console's radically different hardware couldn't support current-gen Xbox games, accusation perfidy in Redmond began to fly. "The solution Microsoft has reached is apparently to recompile current-gen Xbox games so that they can be played on the 360," says G'biz. "First on the list, it says, are the best-selling Halo titles." However, Xbox owners were the only ones freaking out. The usually recalcitrant Microsoft bypassed its external public relations company, telling GameSpot directly that, "Our goal is to have every Xbox game work on Xbox 360. You will NOT need to purchase a new 'version.' Your original games will work on Xbox 360."

Bogus or not bogus?: Bogus.

KTRIC

I'll believe it when I see it with my own eye's.

Ciaran500

Believe what?

KdjaCL

/me bets Msft release the source code to every one of their games to let the modding community recompile them.

The PR beast that it is would only host the best on its Live product for download.

kdjac

CiDeRmAn

Well what the hell am I going to do with my Steel Batallion and controller, was kinda hoping for a next gen sequel, ah well, such is life....

Please..
Leave now...
I must weep....

Ciaran500

KdjaC wrote:

/me bets Msft release the source code to every one of their games to let the modding community recompile them.

The PR beast that it is would only host the best on its Live product for download.

Did you read the link me or jesus posted. They don't need to be recompiled.

KdjaCL

Ciaran500 wrote:

Did you read the link me or jesus posted. They don't need to be recompiled.

That news is a weeek old, most do only games that use a GL basecode dont have to be

That leaves about 70% of games to redone, to be expectd really with the switch in g card. Their best cheapest option is to let modders run riot with the games and release them tru Live. Wont lose money as the games will be done on a age basis but will earn Kudos for giving away games sort of.


kdjac

Ciaran500

GL? Don't all games on the Xbox use a modded Dx code.

KdjaCL

Nvidia had some sort of GL lightmap thing going on with the last GPU , ATI obviously dont use it (so i been told by an Xbox original Dev team member)


kdjac

Ciaran500

They must of found a way around using the nvidia code as some of the "top selling games" that they mentioned in E3 conference will be using it.

flogen

Check out bungie.net for this weeks update, the guy says that while he doesn't know for sure, he doesn't think you'll have to buy any new titles, just put your old games in.

If they do need to release new discs they may as well not bother, or sell them for a fiver each. I'd say they'll either be emulated or nothing.

po0k

They could easily just mail off discs with the modified engine etc. to people who requested one for their XBox1 copy to play the game on the XBox360. Ie Boot off the mod-disc, and pop your original disc in from which the XBox 360 streams the game content. Or even just have the 360 version of a given game's engine be made available for download through live, again with the original disc being used as the game content source.

monument

SyxPak wrote:

They could easily just mail off discs with the modified engine etc. to people who requested one for their XBox1 copy to play the game on the XBox360. Ie Boot off the mod-disc, and pop your original disc in from which the XBox 360 streams the game content. Or even just have the 360 version of a given game's engine be made available for download through live, again with the original disc being used as the game content source.

http://blogs.guardian.co.uk/games/archives/2005/05/20/rumours_of_xbox_360_nonbackwards_compatibility_explained.html

"We’re not sure where this came from, and is incorrect. At launch, Xbox 360 will be backward compatible with the top Xbox games. Our goal is to have every Xbox game work on Xbox 360. You will NOT need to purchase a new ‘version’ — your original games will work on Xbox 360."

:rolleyes:

jesus_thats_gre

read it this time, quote from microsoft!!!!!!!!!!!!!!!!!!!!!! wrote:

he usually recalcitrant Microsoft bypassed its external public relations company, telling GameSpot directly that, "Our goal is to have every Xbox game work on Xbox 360. You will NOT need to purchase a new 'version.' Your original games will work on Xbox 360."

ffs

po0k

Yeah.

You won't need to purchase anything.

You may still have to request discs, or in a far more likely scenario, you pop in the XBox1 discs into the 360 and it downloads what it needs off Live!.

Read between the lines.

Ciaran500

SyxPak wrote:

You may still have to request discs, or in a far more likely scenario, you pop in the XBox1 discs into the 360 and it downloads what it needs off Live!

FFS, read what is posted. "you do not need to recompile your Xbox games" "your original games will work on Xbox 360.”" This means no changes, no downloading, no free disc you send off for. Stick the game in and it works.


Why are people finding this so hard to take in, yet people believe every bit of bullshit sony spout.

steviec

There's no issues with backwards compatibility. The X-Box 360 will emulate the X-Box. Which means it will play x-box games out of the box, there's no new versions, no recompiling.

Microsoft is just being careful with its words because consoles are very very complex these days and an X-Box is hard to emulate perfectly, and it could be possible that one or two games will slip through the net and not work. And they say 'top-selling games' because they're obviously the ones that'll be tested the most and should be emulated perfectly, while more unusual games might have more of a chance of having glitches. I'd expect 99% of games to work though.

bk

Ciaran500 wrote:

FFS, read what is posted. "you do not need to recompile your Xbox games" "your original games will work on Xbox 360.”" This means no changes, no downloading, no free disc you send off for. Stick the game in and it works.


Why are people finding this so hard to take in, yet people believe every bit of bullshit sony spout.

Because as a programmer I know that it just isn't that easy. The Xbox 360 has a completely different architecture to Xbox.

Xbox uses Intel, CISC based processors.
360 Uses IBM, RISC based procesors.

You literally can't get two more different architectures. Read the following to see how different they are:

The primary fallacy of the "RISC and CISC have converged" school of thought is to ignore the distinction between an instruction set architecture (ISA) and the internal microarchitecture of an actual processor implementation. RISC and CISC refer to ISAs, which are abstract models of computer architectures as seen by the programmer. An ISA includes the programmer and compiler visible state of a computer, including all registers and flags, the encoding and semantics of all instructions, exception handling, and memory organization and semantics (little-endian vs big-endian, weakly-ordered vs strongly-ordered). An ISA does not tell computer engineers how an implementation must be realized.

Today's modern x86 CISC microprocessor and high-end RISC microprocessor share a great deal of implementation details and are built using similar functional building blocks. The integer out-of-order execution back end of a Pentium II/III or K7 Athlon processor with its large group of renaming registers does closely resemble the integer data path of a RISC processor. This similarity is a major reason why x86 processors haven't fallen hopelessly behind the performance of RISC microprocessors, but CISC processors still pay a large complexity tax. A modern x86 processor requires several extra pipe stages and about 40% larger instruction cache to analyze the variable length x86 instruction set and store pre-decode information. The x86 instruction decoders themselves consume one or two million transistors and are quite complex and prone to design errors that are only partially correctable using patchable microcode store. The modern x86 back-end execution engine (the so-called "RISC execution unit") also has to devote extra resources to handle instruction dependencies related to condition codes and ensuring exceptions encountered, while processing micro-ops can be reported back as precise exceptions within the context of the originating x86 instruction.

Also Xbox used a Nvidia GPU while 360 uses ATI. Again these are different architectures.

I'm not saying that it can't be done, but it certainly isn't easy or cheap for MS to do.

Doing it with emulation is going to be very hard, if not impossible. In particular, emulating the Nvidia GPU would be incredibly hard. Nobody has ever managed to sucessfully emulate a modern GPU, what a GPU does is simply far to specialised. A GPU even 4 years old is still probably more powerful at what it does then even a modern three core CPU.

What is more likely is that MS will re-write parts of the game engines and psuedo emulate certain parts through an ATI GPU. This would require either a download or getting a new copy of the game and it won't mean all gamess will be available from day one, it will take time to get each game working.

monument

steviec wrote:

There's no issues with backwards compatibility. The X-Box 360 will emulate the X-Box. Which means it will play x-box games out of the box, there's no new versions, no recompiling.

Microsoft is just being careful with its words because consoles are very very complex these days and an X-Box is hard to emulate perfectly, and it could be possible that one or two games will slip through the net and not work. And they say 'top-selling games' because they're obviously the ones that'll be tested the most and should be emulated perfectly, while more unusual games might have more of a chance of having glitches. I'd expect 99% of games to work though.

Oh, then, please give us a link to a quote where MS says "There's no issues with backwards compatibility". What is you 99% based on?

And it's 'Xbox' by the way.

Gizzard

xbox360 must be backwards compatible or theyre DOA

astrofool

I could 100% guarantee that Microsoft will not be so stupid as to re-release current xbox games re-compiled to have to work on xbox360.

If people remember, the ps2 and ps weren't 100% backwards compatable either, just most titles worked, and it will probably be the same with the xbox360.

(of course thats not to say that we won't see older games updated, like capcom did with resident evil, or nintendo do with the likes of mario all-stars, but thats a completely different thing).

Ciaran500

bk wrote:

I'm not saying that it can't be done, but it certainly isn't easy or cheap for MS to do.

Doing it with emulation is going to be very hard, if not impossible. In particular, emulating the Nvidia GPU would be incredibly hard. Nobody has ever managed to sucessfully emulate a modern GPU, what a GPU does is simply far to specialised. A GPU even 4 years old is still probably more powerful at what it does then even a modern three core CPU.

What is more likely is that MS will re-write parts of the game engines and psuedo emulate certain parts through an ATI GPU. This would require either a download or getting a new copy of the game and it won't mean all gamess will be available from day one, it will take time to get each game working.

http://www.qbrundage.com/michaelb/pubs/essays/xbox360.html

"the more you understand what it needs to do, the more certain you are that it's impossible, and consequently the more amazed you are to see it in action."

"some people observe the CPU and GPU architectures are utterly different between the Xbox 360 and the Xbox, and then speculate about the difficulties those differences pose for emulation. Without really understanding anything that's involved, they're already convinced that backwards compatibility is a difficult task."

"So a few people who understand how emulators work look at these numbers, impressive as they are, and conclude that Xbox backwards compatibility will not work."

Sounds like he's talking about you

Gizzard

astrofool wrote:

I could 100% guarantee that Microsoft will not be so stupid as to re-release current xbox games re-compiled to have to work on xbox360.

If people remember, the ps2 and ps weren't 100% backwards compatable either, just most titles worked, and it will probably be the same with the xbox360.

(of course thats not to say that we won't see older games updated, like capcom did with resident evil, or nintendo do with the likes of mario all-stars, but thats a completely different thing).

astrofool is right

steviec

monument wrote:

Oh, then, please give us a link to a quote where MS says "There's no issues with backwards compatibility".

“We’re not sure where this came from, and is incorrect. At launch, Xbox 360 will be backward compatible with the top Xbox games. Our goal is to have every Xbox game work on Xbox 360. You will NOT need to purchase a new ‘version’ — your original games will work on Xbox 360.”

Again, they're just covering their tracks. The PS2 wasn't 100% backwards compatible either.

stevenmu

As a (barely) educated guess I would say they would use some form of just-in-time translation, one or two of the cores being dedicated to translate old xbox code from the disc to new Xbox360 code. The vast majority of graphics code would have been written using the DirectX api so this could easily be translated, I'd guess the few games they expect to not work would be ones bypassing this api and directly using feature of the Nvidia card (or other aspects of the Xboxs hardware). This would be much simpler to implement (given that MS have full access to all the machine level details of both consoles) and more efficient to run than a genuine emulation of the xbox. Their VMware technology would probably be of some help with this too.

Gizzard

steviec wrote:

Again, they're just covering their tracks. The PS2 wasn't 100% backwards compatible either.

er yes it was

flogen

Gizzard wrote:

er yes it was

no it wasn't, some ps1 games didn't work

bk

flogen wrote:

no it wasn't, some ps1 games didn't work

PS2 actually included a PS1 on a separate chip[1]. There were a few games that didn't initially work, but these were later fixed with PS2's with a new BIOS.

The problem was that the code wen't through the PS2 chip before being transported to the PS1 chip. Some games used non standard PS1 API's that then broke down. However this was easily fixed by a later PS2 Bios.

[1] The Nintendo DS does the same and has a separate GBA chip. PS3 is likely to also be the same with a separate PS2 and PS1 chip. It is by far the easiest way to do backwards compatibility.

nednedned

wait and see--if not to your taste--wait for the ps3--they said theirs
will be BACKWARDS COMPATABLE.any idea on price of x-box 360
and ps3.


cheers..............

bk

Ciaran500 wrote:

http://www.qbrundage.com/michaelb/pubs/essays/xbox360.html

"the more you understand what it needs to do, the more certain you are that it's impossible, and consequently the more amazed you are to see it in action."

"some people observe the CPU and GPU architectures are utterly different between the Xbox 360 and the Xbox, and then speculate about the difficulties those differences pose for emulation. Without really understanding anything that's involved, they're already convinced that backwards compatibility is a difficult task."

"So a few people who understand how emulators work look at these numbers, impressive as they are, and conclude that Xbox backwards compatibility will not work."

Sounds like he's talking about you

Interesting read, I never said it wasn't possible, just that it is hard.

Alan Turing (the father of computers) work in the field of computability theory with his universal Turing machine taught us that any machine can emulate any other machine, as long as the machine doing the emulation is sufficiently powerful.

However the Turing machine is a theoritical machine with infinite memory and it doesn't say anything about the emulated mahine running fast or the real world implementation problems that it involves.

I'm really hope that I'm wrong, that MS come out and amaze us all with 100% backwards compatibility. While Michael's post is interesting, it has far too little real substance and uses the world "magic" far too much for my liking (in fact using the word magic even once usually makes me with to hurl!!). I'm looking forward to seeing what they have.

BTW I fall into the second camp he mentions above rather then the first

silverlining

MS are getting great publicity out of this rumour mill while they give vague answers over and over again. I'm just going to wait and see

evad_lhorg

whoa this started some angry people off. jesus!

VIVA Lá REVOLUTíON!!!!!!!!

monument

steviec wrote:

Again, they're just covering their tracks. The PS2 wasn't 100% backwards compatible either.

Maybe, but stuff like this makes me think MS just don’t know, don’t have a clue, or at least they’re not sure, or maybe just bullish...

http://gamestoaster.typepad.com/games_toaster/2005/05/streaming_music.html