Xbox One (Durango) Technical hardware investigation

[DieH@rd]

Xbox One Architecture Finally Explained – Runs OS ‘Virtually Indistinguishable’ from Windows 8

A few months back, many news outlets reported that Xbox One runs 3 Operating Systems. They further went on to claim that the one was a stripped down version of Windows 8, one was the Xbox One OS and the last was a switching layer between the two. Well they were wrong. Xbox One does indeed run three operating systems but the correct ones are: a full fledged windows 8, a stripped down windows 8 and a Host OS (RTOS). The implications for this are immediate and stunning and we will go upon each in this article.

We recently received the slides from Frank Savage’s presentation at Build 2014 along with the audio of the same. And we noticed something that many news outlets failed to report. The fact that Xbox One runs Windows 8. Not only that, but we realized that so many of the news outlets had gotten the initial leak completely wrong. Because if you run a game or an app on the Xbox One, it will either run in the full Windows 8 or the stripped down version of Windows 8. Either way it runs on Windows 8. Let me start by explaining the three operating systems present in Xbox One.


The first tier ‘Host OS’ and the ‘to-the-metal- operating system present in Xbox One dubbed the ‘Host OS’ is an RTOS (Real Time Operating System) has complete control over the entire Xbox One hardware and resources. In Frank Savage’s words “… owns where everything and how everything works…. owns CPU…GPU”. This is your basic Xbox One Operating System. However the thing is , this particular OS only handles tasking and the security layer. It does not run any game or application. It does however host (in a non – hyper-v form) the ‘OS’ and the ‘Exclusive OS’, which is Windows 8 and the stripped down Windows 8.

The second tier ‘Shared Partition’ is occupied by Windows 8. This Operating System is “virtually indistinguishable” from the Windows 8 we know (and love?) , code wise. This particular Windows 8 handles all the basic functions of the Xbox One including the shell. Shared Apps are run here. It handles some major features of games such as networking and some audio.

The third tier ‘Exclusive Partition’ is the Exclusive OS, which in Frank Savage’s words is a “windows 8 that has gone on a massive massive diet…… lean and mean windows 8″. It has been hand tuned to remove any and all bottlenecks as well as bloatware. However this is the part which defines it as a ‘partition’ and not a virtual machine. All the Direct X draw calls go straight from the Exclusive OS down to the Host OS. It does not go through the full windows 8 ‘ shared partition’.

Basically the Xbox One is a true X86, X86-64 machine. As Frank Savage said, “any game I made ran equally well on Windows 8 (desktop) and Xbox One”. The porting capability this implies is very powerful, infact, if Frank Savage is to be believed, port-lag is non existent. Just convince the devs, and you shall have the game.

http://wccftech.com/xbox-one-architecture-explained-runs-windows-8-virtually-indistinguishable/

 

[XpiderMX]

http://wccftech.com/xbox-one-architecture-explained-runs-windows-8-virtually-indistinguishable/

Any "pros" for using a "full" Windows 8 OS?

 

[Deleted member 86764]

I'd guess that the 'pros' are being more easily able to multitask apps and a game. Though it's debatable as to whether that's really much of a pro at all. The OS seems very bloated to me.

 

[TomRL]

Will it ever be possible to fit a 1080p framebuffer on 32mb?

 

[XpiderMX]

http://wccftech.com/xbox-one-architecture-explained-runs-windows-8-virtually-indistinguishable/

I'd guess that the 'pros' are being more easily able to multitask apps and a game. Though it's debatable as to whether that's really much of a pro at all. The OS seems very bloated to me.

But it can be done with a streamlined Windows 8 OS. Can't understand why a full or practically full version.

 

[mosen]

But it can be done with a streamlined Windows 8 OS. Can't understand why a full or practically full version.

They can update XB1 OS to full windows 9 and 10 in future since it's not an specialized OS?

 

[Shifty Geezer]

Will it ever be possible to fit a 1080p framebuffer on 32mb?

Yes, easily. A 32 bit RGBA framebuffer fits in a quarter of that. You can thus fit HDR buffers. The problem with the ESRAM capacity is the working space for multiple buffers while creating the framebuffer.

 

[Nisaaru]

unless you are running real close to the metal or using software loop timings.

With the 6 cores running your game code/3D driver, CPU Inst/Data prefetch/speculation, OS/Network events and Mpeg encoder you have no predictable timing. I can't see how anybody could even depend on true realtime timing here at all and pass any quality tests. So I would say this would be a non issue.

 

[Cyan]

http://wccftech.com/xbox-one-architecture-explained-runs-windows-8-virtually-indistinguishable/

I think that's very good news for easy portability. Maybe the universal apps feature has been planned since long ago.

 

[bkilian]

http://wccftech.com/xbox-one-architecture-explained-runs-windows-8-virtually-indistinguishable/

Man, that article got so much wrong it's impressive, especially considering they had the slides and audio.
1) The exclusive partition is indeed a "Stripped down win8". Exactly like the 360 OS is a "strppped down win2000". You _will not_ be able to run a game compiled for windows on the exclusive OS without recompiling it. That alone should tell you that they're not the same.. You may also have to change code, but that depends on whether you want to take advantage of the xbox specific APIs.
2) The system OS may be close to retail Win8, but OS services will be different. For instance, the shell code will be different. However, if you write a modern app without relying on shell bits like contracts etc. It may run. It may also need recompiling. Desktop apps will not work. Think an x86 version of WinRT.
3) And guess what? The Host OS is _also_ windows 8! In fact, when I left, Host OS and Exclusive OS were compiled from the same tree.

 

[pjbliverpool]

So it sounds as if it should be pretty easy to run native PC games on the XB1? That could certainly be interesting.

And looking at it from the other side of the coin, the XB1 is sounding like it might be the easiest console of all time to emulate on the PC, especially once games start to be made on DX12. Same API, same OS and same hardware.

EDIT: read bkillians post after posting this - so I guess things aren't quite that straight forward afterall.

 

[XpiderMX]

2) The system OS may be close to retail Win8, but OS services will be different. For instance, the shell code will be different. However, if you write a modern app without relying on shell bits like contracts etc. It may run. It may also need recompiling. Desktop apps will not work. Think an x86 version of WinRT.

Something like "Windows Core Server"?

I was suspecting that it was a misunderstanding of the web.

 

[dobwal]

Don't know how applicable it is now. But here is a patent that explicitly describes the XBO hardware and its resource allocation.

https://www.google.com/patents/US20...a=X&ei=t3BVU86sLsjf8AGKpoHQBw&ved=0CEUQ6AEwAg

Breaks down utilization of resources for each mode down to the cpu, gpu, MEC, DMEs, Audio, Memory, HDD, ODD, esram and etc.

 

[shredenvain]

Will it ever be possible to fit a 1080p framebuffer on 32mb?

It has already been achieved by several launch games like Forza 5(1080 60fps),
Nba2k14(1080p 60fps),Madden,Tomb Raider DE, all Lego games just to name a few.
Why do people have the impression that the X1 is incapable of 1080p because of the esram?
Even if the 32mb esram was too small in some situations it has already been stated that the framebuffer can over flow into the main memory. Thats why I hate what gaming journalism has become on the web. They constantly post stories with headlines full of half truths to get traffic. Sure devs are having trouble hitting 1080p 60fps on some titles for the X1, but now the misconception that 1080p isnt possible on the X1 is becoming fact to alot of people.

 

[XpiderMX]

Sure devs are having trouble hitting 1080p 60fps on some titles for the X1, but now the misconception that 1080p isnt possible on the X1 is becoming fact to alot of people.

Devs are having troubles even for 1080p/30fps, that's weird.

 

[pMax]

https://www.google.com/patents/US20...a=X&ei=t3BVU86sLsjf8AGKpoHQBw&ved=0CEUQ6AEwAg

...I wonder when this flow-chart patent madness will end...

anyway, that patent is only a claim for a low resource mode which, honestly, reminds me terribly the one of Android and similar platform, where the FG app can steal resources from BG apps that might need to re-create their objects.

flow-chart patents... bah...

 

[zed]

Any "pros" for using a "full" Windows 8 OS?

Less likely to have bugs etc, casuse it should be better tested. Cost savings as well.
Also I assume with the new consoles (even last gen) theyre practically doing everything a PC is anyways, so why not.
Its a good reason IMO have a near identical OS as weindow 8. (sure minus some of the hardware stuff)

Then again surface shipped with about have the storage full for the OS (google it if you dont believe me), so perhaps the OS makers are incompetent . Though with xbone it has a 500GB HDD thus 20GB for the OS is not so bad

 

[shredenvain]

Devs are having troubles even for 1080p/30fps, that's weird.

Yeah Thief is the only 30 fps title on the Xbox one that is under 1080p that I recall at the moment. Thats exactly the kind of thing my post above was talking about.
People are all under the impression 1080p is near impossible on the X1.
Several developers have stated that 60fps is what gives them difficulty hitting 1080p.
Sebbi even stated that it is much easier to hit 1080p at 30fps on the X1 than it is 720p 60fps.

 

[Brad Grenz]

Yeah Thief is the only 30 fps title on the Xbox one that is under 1080p that I recall at the moment. Thats exactly the kind of thing my post above was talking about.
People are all under the impression 1080p is near impossible on the X1.
Several developers have stated that 60fps is what gives them difficulty hitting 1080p.
Sebbi even stated that it is much easier to hit 1080p at 30fps on the X1 than it is 720p 60fps.

AC4, Ryse, Dead Rising 3, Tomb Raider's cutscenes and reportedly Watch_Dogs and Witcher 3, in addition to Thief.

 

[Pixel]

Watchdogs will be 1440x960.

In the case of Watch Dogs have a feeling its more of a memory system (ddr3 bandwidth and/or esram cache size) issue rending large open world at a certain setting/iq.