The Xbox Operating System

Sorry it’s been a while since my last post – blogging is hard to keep up with, especially when it’s not your job.  I’m off to Japan next week, so it will probably be another week of silence before you hear from me again.

One of the first questions I get when someone hears I work on Xbox is “So, what operating system do you guys use?  Windows 2000, right?”  I am honestly not sure where the Win2K misperception comes from, but Xbox runs a custom operating system built from the ground up.  While our operating system exports many of the same APIs found in Win32 (e.g. CreateThread or WaitForSingleObject), not everything is there.  For instance, there is no use for CreateWindow on Xbox – all graphics are done through (our own flavor of) Direct3D.

There are a number of reasons both Xbox and 360 have their own OS.  First, it gives Xbox a chance to own its own destiny in terms of architecture.  When you have your own operating system, it’s easy to go in and change things.  Second comes performance.  There isn’t much of a hardware abstraction layer on Xbox – most stuff talks almost directly to hardware.  This eliminates a lot of software overhead you might find on a PC.  Third is security.  With our own operating system, it also becomes a lot easier to design & implement our own security architecture.  As the community is finding out, there is a lot of custom stuff.

The operating system is more than just the kernel.  On Windows, you have critical components such as explorer.exe, shlwapi.dll, user32.dll, and others that are required for your system to function.  On Xbox 360, we have similarly critical components.  When you see a required system update from Xbox Live, we are mostly updating these critical components with fixes as well as new features.

That’s a primer on our operating system.  I wouldn’t want to spill all my guts in one post ‘cuz then I’d have nothing to talk about later on.  Let us know if you want to know more about the OS in the comments…

Comments (52)

  1. Nick says:

    Wow, I guess I really am a nerd for knowing that, that’s a nobrainer.  From now on when people ask you about the OS you should just say "Why Linux of course"

    gt-Feelz Good

  2. Skullfire says:

    "On Windows, you have critical components such as explorer.exe, …"

    Who said developers didn’t have a sense of humour!

  3. tzagotta says:

    It’s interesting that WinCE is not used. The message from MS is that WinCE would meet requirements for a device like this, but when XBox was designed, the old "roll-your-own-RTOS" decision with typical justification was made. It would have been a much better story for WinCE if it ran XBox.

    Thanks for sharing this information… Really interesting.

  4. Ric says:

    My question on the OS is that in terms of features and functionality, will it continue to be significantly improved over the lifetime of the console or is their only plans to get it to a certain set of features and then cease development except for bug fixes and security updates?

    While I know you couldn’t say much about future features and updates if they are in the works, I’d hope that not only will Microsoft be competitive with other console developers (if needed) in terms of features but will continue to innovate in the living room area and not just through Media Center.

    I would easily pay the cost of a full game for a fully featured internet application sweet that would let me check my e-mail(imap please), surf with a fully featured browser, read rss feeds or even let me admin my servers via a tv formatted terminal services client. Heck you can sell me a first party wifi xbox live keyboard and mouse to go with it also.

    While alot of this functionality can no doubt be found in similar apps made by third parties for running on the Media Center platform, you wouldn’t be able to beat an optional "Internet" blade on the dash board with these features made by Microsoft.

    So regardless of whether or not these features are coming, how aggressive is Microsoft being about bringing any new features typically reserved for desktop platforms.


  5. RyanSchneider says:

    Would it be possible to port .NET to the 360 for Xbox Live arcade development?  By ‘possible’ I mean practical, by which I mean ‘do you guys have any plans to do this’? 😉

  6. That’s very cool. Is it possible for external developers to write applications on the OS APIs? Are they documented any where? And, I was interested on Ryan’s question about .NET for the XBOX…

  7. Недавно с удивлением обнаружил, что Microsoft создал и давным-давно продаёт ещё

  8. Nick says:

    I’m curious if the Xbox OS has any sort of background disk defragmenter for the hard drive. Something similar to what Windows has, except it runs as needed in the background instead of when the user tells it to. With the size of Xbox 360 hard drives set to grow (hopefully) soon, game data caching, and the increase in XBL content, I would imagine that the file system could eventually become pretty fragmented and drive performance could be impacted.

    Though it isn’t directly related to the OS, I will third it since somebody else already brought it up. The ability to use C# for XBLA games would be an amazing bonus to the Xbox 360 development process. I think there are a LOT of indie developers out there who definitely want to hear a "yes" or "no" from Microsoft on C# support for Xbox 360. Are there any plans to support C# (in its managed capacity, of course) for Xbox 360 development?

    Thanks for your time,


  9. Bill says:

    More info on the OS please! It’s interesting.

  10. Wiggy says:

    Enough of this fluff… I once again request multi-person voice chat! Provide! That is all. Thank you.

  11. Lewis says:

    I agree with Ric. Also, I doubt they’ll let us develop our own apps for security reasons. It’s a shame though, I could think of hundreds of cool things to do 🙁

  12. dricas says:

    would it be possible in the future, you guys release a Dreamcast emulator for the XBOX 360? I mean, it was based on WinCE or something like that. I bet millions will pay for it via XBOX LIVE ARCADE. In fact, you should start doing official emulators for Sega consoles, like Sega CD, Saturn, DC. How cool is that? not only backward compatible with XBOX, but with Sega too.

  13. PatriotB says:

    I don’t know where I first saw it, but since the announcement of the original Xbox I’ve read that its OS was a customized version of the Windows 2000 OS.  Interesting to hear that it actually isn’t.

    Though it is pretty obvious that it’s some sort of NT-like system.  Given, for example, that there is a IMAGE_XBOX_SYSTEM constant in the Windows header files to indicate that a PE file is designed for Xbox.

  14. digiguru says:

    I noticed that the market place can get a little lengthy to browse, in the future it will need updateing. I expect this will be a likely enhancement. I disagree with what Ric said, keep the mouse out of the house. This is a family room. Get voice regognition technology or gestures to really make my TV surfing a family activity.

    Are we likely to see more blades appearing in the OS? There are rumours of a Direct TV blade across the web (i’d suggest this is rubbish) – but will we see the catagories change and grow? From a UI Design point of view i’d guess you guys want to keep the blade catagories, and organise the content within each blade.

    PS – I’m loving the microsoft brand these days (i’m a convert FROM mac!).

  15. johner says:

    A .net environment running isolated from the rest of the xbox would be very useful, like the emulator for xbox 1 runs as an app, the .net framework as an app would be a happy compromise. No real need to get full access to hd for example just an isolated area/partition.

  16. THE MADBARBER says:


  17. Cra says:

    You can’t run code even if there is a Browser in the OS.

    You can just give it a virtual machine, as soon as memory goes beyond the bondary, it shuts it down. And of course, nothing is executable within this memory area. That makes it a pretty "easy" way to prevent any buffer overflow/underruns, and since the Xbox requires signed code, you are pretty much left out for running any code at all.

    So no, unless the 360 is hacked that unsigned code can run, it would be highly unlikely to affect it with a virus. That’s just as smart to think/say as the auto-run exploit working on an Xbox, it just doesn’t work that way anymore nowadays 😉

  18. InsaneBastard says:

    It would be interesting to hear how the updating of the OS works.

    When the XB 360 "hangs", or suffer any other problems, does the errors get logged and sent to MS for troubleshooting? Personally I would feel better if the dev teams got logs from my console whenever I suffered a problem.

  19. InsaneBastard says:

    If you are able, do you think you could comment on the DVD playback issues a lot of people are having? For example when the audio and video gets out of sync. (Happens to me a lot for example, then every few minutes the xbox "corrects" itself, and the audio is in sync for s hort while).

    Why doesn’t the XB 360 support other keyboard layouts than american? (I can’t write the swedish characters åäö when I write messages for example.)

    Why is the messages limited to about 260 characters in the XB 360 messaging system?

    It would be nice if it was possible to deactivate the notifications for DVD playback. (but make them still appear if you play games)

    I would also like to thank you for posting about what happens behind the scene. There are a lot of tech freaks out here who are really interesting in how everything works. 🙂

  20. InsaneBastard says:

    I agree with Ric on the subject of internet browsing. That would be really cool! Several attempts have been made in the past, but since SD-TV had too low resolution + interlacing, browsing the web on your TV was a real pain.

    Now with HD-TV it could actually work! I see however some problems with it. I’m thinking mainly about the ads then, but also about scripts. It would have to be a damn secure browser so it could not affect the rest of the system. But oh it would be so cool if we could get it 🙂

  21. InsaneBastard says:

    The Xb 360 could have the potential of becoming a true hub for all our entertainment AND information needs. If MS play their cards right, they could really dominate the PS3.

    Sorry for my several posts. I’ve got so many ideas 😀

  22. Byakuya says:

    I know microsoft has said they don’t want to own the living room, but the 360 is well equipped to do just that.

    Also I don’t know if you can answer this one, but is the 360 operating system at all comparable to the unreleased windows vista?  I’d like the 360 to be capable of fully taking advantage of vista.

  23. Bagpuss says:

    For one comment on the OS I’d say is, why is the network support much more flakey on the 360 compared to the original Xbox. Lots of people I play with in the UK get 2 or 3 disconnects per session. Yet when we play games on the vanilla Xbox all is fine.

    Is the tollerance to network quality much lower on the 360 implementation of live? i.e. what would be OK on the vanilla Xbox would disconnect you on then 360?

    I would have thought that a revised OS would have been designed to be more tollerant or at least more informative about network problems.

  24. Lewis says:

    It’s probably just their Xbox exploding… happens to me all the time 😛

  25. Interloper says:

    As near as I can tell, the origin of the Windows 2000 story is at

    Basically, that says that the original Xbox OS had its roots in Windows 2000 (but was quite a bit different by the time it was retooled) and the Xbox 360 OS had its roots in the Xbox OS (but was similarly redone).  Is this a somewhat accurate portrayal of events?

  26. InsaneBastard says:

    I’m a swede who’s a bit unhappy with how the Xbox 360 handles the keyboard support. How come there’s no support for western european keyboard layouts?

    I can’t write in my own language properly when using a keyboard, but is limited to write in english. Not that I have any problem writing in english, but it feels weird though to write in english to people in your own country, just because the Xbox 360 can’t handle western european keyboard layouts.

    I wonder how it works for the japanese or the russians 😀

    Anyway, I hope someone takes a note of this. We should be able to choose keyboard layouts in the console settings me thinks 🙂

  27. InsaneBastard says:

    In regards to my post above; if support for western european keyboard layouts is "impssible", i.e Microsoft doesn’t want to spend time correcting the problem :-P, at least give us the possibility to write special characters using ascii code.

    I would be accept holding down alt for example and pressing 229 to get an "å".

  28. Megamuch says:

    Love the x360, hate the multilingual support for Live!

    I’m dutch, live in Spain, but would like to recieve the arcade info and such in english. For some *&%^$#$# reason, this seems impossible. Too bad.

    Back to the OS,

    If you look at it from a traditional OS (let’s say win98+) point of view, how advanced is the Xbox OS?

    Does it use any cool tricks that could/should be implemented in any future MS OS?

  29. sachin says:

    Can we get a list of APIs which are supported on XBOX  and which are there in windows OS (e.g.XP, 2003, Win2k).

    Is there any such document? This is important if we wnat to post any component from windows to XBOX.

  30. Garry Trinder says:

    sachin: sorry, documentation for the Xbox 360 Development Kit is subject to being an approved Xbox 360 game developer.  I’m sorry that I can’t publicly show the information you are asking for.

  31. pocoster says:

    im not questioning whether this guy does work for microsoft or not but i do hav one argument to make and that is that on my course of game development i was told by my teacher ( a former programmer of microsoft) that the xbox uses a stripped down Windows 2000 kernel (500k size) im not sure wot he said about the 360 os but hey wundered if u cud shed sum light on this????

  32. Kryztoval says:

    About the multilingual thing… yeah, it’s a pain, my passport account was made in mexico, then it had spain cause i was there, then i switch it back to mexico, when i created my gamertag… guess what? it says spain! I do prefer the console to be in its home lenguage (yeah, if it were japanese i would use it in japanese!) but that’s not it (mexico and spain speak spanish) but i get all the prices in euros!!! which, shouldn’t you know it, it’s about a 40% increase in price! darn.

    Getting back to the OS part… I would love to be able to make software for my own xbox, or to use it for websurfing, chatting or the like, why do i have to pay for another OS when i could browse on my xbox?! Darn, i love that darn hardware, sleek, sweet, nice, smooth, is too bad that it has such a big power cord. BTW I do remember reading the OS was a customized version of windows 2000 (for the original xbox) which sounds to be the case, due to the date when it was made) and, if, as you say, this one is made from the ground up, and made with so much low level code (let’s hope assambly) then why is it that the dashboard DOES slow down during some games which are not that graphic intensive? I still sense some layers of abstraction from hardware or that would not be the case, c’mon… if the dashboard is up, shouldn’t it have the highest priority as it is the core app?

    On the other side, not having a good tutorial as to what videos one can play, not permiting copying of mp3 audio contents from memories nor cd’s, only allowing ripping, and the fact that some original cd’s won’t be read (have you ever tried the Half life 2 sound track disc? well, no luck with any of the originals, copy it to another disc, an voila!) Hardware was well selected for some minor disgraces (capabilities, such as reading a toc that begins way before the original ones, etc) but not being able to read an audio cd? that just blows it… the os restrictions is another blow… how many blows before users decide to find a way around that? think twice, PS3 Promised to be an open developer platform, if it is, I may as well just buy one or two just to be able to program for it, and who knows, we may even be able to make the PS3 compatible to the xbox360, such is the power of developers, whom you just cut off.

  33. Mevan Alles says:


    I’m a Computer Science Student Of University Of Moratuwa ,Srilanka.

    For an assignment I have to write a submit a report  on "XBOX 360’s " Operating system. Please be good enough to tell me some website that I can get information on this topic.

    Cheers 🙂

  34. Xbox Team says:

    Hello Everyone,


    My name is Daryl Welsh, (GT: IndieGames).  I’m the Test Manager for Xbox…

  35. Joah says:

    i felt so sad now… because my xbox 360 hang after playing whatever games for 5 mins. i don’t know why… but before it hangs i update it’s software when i insert BATMAN BEGINS xbox game. when i insert xbox 360 games… it just can’t work. some don’t even start up… what really happen?

  36. ktula says:

    I have owned a Xbox 360 for more than 2 months and based on my experience so far, i think it is still a beta product.  My Xbox 360 consistently hangs – while in game play, while downloading movie trailer, while playing movie trailer, while playing songs from my iPod, etc…

    Worst of all, Halo 2 seriously lags in Live play.  

  37. M1Tanker says:

    I am interested to know if there is a fix for the crashing that occurs when you are playing a game that creates large save files(like Elder Scrolls). If there is a fix for this please e-mail me, I have been sitting with a half completed game for almost 2 years because it starts crashing when you get about halfway through it.

  38. paul says:

    hmm xbox used alot of Windows NT kernel (sure a snapshot from w2k) but still NT kernel.

    You may have customized alot of the API layers you expose but NTOSKRNL is still there … 🙂

  39. leo says:

    i think  that   you should be able to  make  up back up  HD. for the  xbox  because  xbox has  hard drive  crashing, and thay  only  give a  90day war.  for  xbox  seening  xbox is  set up like  a computer  running  the operating System of lunix , the only  big diff. that the bois is wroten in revurs

    and so  on  i think that should  sell back up harddrive,s and  not  kill in cost of  fixing it see that the  harddrive is  only a 6 or 12 gg  harddrive  when them are  onlymaybe 20 dollers  so in closeing    that is  why i have  unlock the harddrive   and  cloned the xbox harddrive to a 160gg HD. and relocked the drive

  40. Marcus says:

    Is it possible to acquire an image of the XBox OS?  My XBox has went kaput(Your XBox Requries Service message with no error code), and I’m suspecting a fried hard drive.  Microsoft won’t fix it because I’ve opened it once before to replace the DVD drive, so I’m looking for some way to get a copy of the XBox 1 OS so I can put it on a new hard drive and get my system up and running again.  You can e-mail me regarding this at

  41. bazoka says:

    i ask if som 1 can buld a os for the xbox an if he can learn me how can i do it



  42. wphi says:

    hello.. Can anybody tell me if xbox supports java?

  43. Jonathan says:

    is it possible to boot an xbox with a cd like you would with a normal computer?

  44. james says:

    it is possible to put another OS such as linux on the xbox but you need a modchip, which is a legal grey area

  45. james says:

    why did they nto use CE anyway?

    was it due to CE’s lack of directx support?

  46. FATE says:

    Is there any way to get ahold of an OS Disk or download the OS from a third party?

  47. Miguel says:

    I feel cheated with this console, I just want to hack it so bad and it won’t let me. That’s what intrigues me of the PS3 people are running operating systems on it already. I just would like to make music on a console on a professional level lol.

  48. dopedogg1976 says:

    i was wondering how to upgrade hard drive for my xbox

  49. Bruce Conant says:

    hey guys, just wondering if there’s a place i can go to download the OS onto my laptop? or just a desktop theme that implements the blade system (such as desktop / my computer / control panel, etc.)


  50. _ko0LaiD_ says:

    microsoft should create a whole different operating for game systems and even maybe regular computers than just building from an older operating system…