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Index > Heap > Is xbox OS, a 32bit pmode Dos OS ?


Is xbox OS, a 32bit pmode Dos OS ?
Yes
27%
 27%  [ 3 ]
NO
63%
 63%  [ 7 ]
Maybe
9%
 9%  [ 1 ]
Total Votes : 11

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Dex4u



Joined: 08 Feb 2005
Posts: 1601
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Dex4u
First before you go off on one, study the spec.
The xbox OS is:
1. 150k in size.
2. single-tasking
3. has direct access to all hardware (including CPU and graphics).
4. Runs in ring0
5. Memory allocation is the responsibility of the app--there's no front-end memory allocation.
6. There's no virtual memory paging
7. The xbox is alow powered PC.

This to me is a 32bit pmode Dos, i have worked on XBOXs, programming them with fasm, the basis xbox OS loads a default file and give it full control (once checks for copy etc are done).
If this is not a 32bit Dos i do not know what is.

More info here: http://www.extremetech.com/article2/0,1697,1670116,00.asp

PS: A lot of what people think is the OS, is done in lib, that are part of the games.


Last edited by Dex4u on 14 Nov 2006, 17:09; edited 1 time in total
Post 14 Nov 2006, 17:03
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HyperVista



Joined: 18 Apr 2005
Posts: 691
Location: Virginia, USA
HyperVista
Here's an interesting MS blog on the Xbox OS:

http://blogs.msdn.com/xboxteam/archive/2006/02/17/534421.aspx
Post 14 Nov 2006, 17:07
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tom tobias



Joined: 09 Sep 2003
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tom tobias
@vid: in my opinion, this VERY interesting topic belongs in the operating system section, not HEAP.
Post 14 Nov 2006, 17:27
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HyperVista



Joined: 18 Apr 2005
Posts: 691
Location: Virginia, USA
HyperVista
I voted yes based on the MS blog from one of the xbox developers who said they "export many of the win32 APIs" from their custom OS.
Post 14 Nov 2006, 17:46
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rugxulo



Joined: 09 Aug 2005
Posts: 2341
Location: Usono (aka, USA)
rugxulo
I didn't vote because I'm not sure what the term DOS means anymore (real mode? flat real mode? unreal mode? V86 mode?). DOS is like C: it's a bunch of things, depending on what the context is (e.g., K&R, ANSI, C99, DOS-specific, POSIX, obfuscated, etc ... DOS 1.0 w/ no dirs and FAT12 meant for 160KB floppies or MS-DOS before 5.0 w/ EDLIN and GWBASIC and only HIMEM or MS-DOS 6.22 w/ MSD, EDIT/QBASIC, EMM386, LH, DOSSHELL w/ task switching, etc., and that's ignoring all the third-party DOSes!).

BTW, somewhat unrelated, but MS had to rewrite its HD-DVD codecs (for their add-on player) for their "PowerPC" XBox 360 machine. How would YOU like to rewrite a bunch of "x86-optimized" code to another architecture?? Plus, the rewrite itself is "4.7 million lines of code"! (I hope a lot of that is comments, sheesh!!).
Post 15 Nov 2006, 04:56
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f0dder



Joined: 19 Feb 2004
Posts: 3170
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f0dder
I've voted no, based on what a vanilla MS/PC/FreeDOS offers.

Yes, the XBOX kernel is stripped compared to a regular NT kernel, but it offers a lot more service than a regular DOS does (heh) - threading, synchronization, blah blah.

Also, keep in mind that the OS is more than the kernel. While it might be distributed with the games rather than the console hardware, I do consider DirectX a part of the OS... and that's a shitload more than DOS has ever offered Smile
Post 15 Nov 2006, 09:03
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Tomasz Grysztar
Assembly Artist


Joined: 16 Jun 2003
Posts: 7712
Location: Kraków, Poland
Tomasz Grysztar
As a 32-bit DOS I would understand the so-called TrueDPMI system - one of the few implementations of it is in NT kernel. However this is just a small (and often unnoticed) subsystem of NT, which is much more than that - as already said above.
Post 15 Nov 2006, 09:38
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Maverick



Joined: 07 Aug 2006
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Maverick
Definitely NO.

DOS+32BitModeExtender is DOS+32BitModeExtender, XBox OS is XBox OS.

The fact that the XBox OS is not as bloated as Vista doesn't make it a DOS+32BitModeExtender anyway. I think++ it has 0 bytes from the old DOS code. Maybe parts of the NT sources are there, though.
Post 15 Nov 2006, 10:00
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f0dder



Joined: 19 Feb 2004
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f0dder
Maverick wrote:

The fact that the XBox OS is not as bloated as Vista doesn't make it a DOS+32BitModeExtender anyway. I think++ it has 0 bytes from the old DOS code. Maybe parts of the NT sources are there, though.


It's based on a stripped NT5.0 (ie., win2k) kernel.

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Post 15 Nov 2006, 10:15
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Dex4u



Joined: 08 Feb 2005
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Dex4u
First thanks for all your inputs .
One thing i need to clear up is the term Dos as i see it, i do not mean Dos as in MSDos or freeDos, but more as in the base design of a Dos type OS.
A Dos type OS to me is a single-tasking, run in ring0, can do direct hardware acsess, no memory protection, in short the program is given full control.
Post 15 Nov 2006, 16:46
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Maverick



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Maverick
I think you're mixing up the old MSDOS times with how most OS's were those times anyway. It's not that CP/M or the 8bit Commodore Kernel or the Spectrum Kernel or the first Apple OS were multitasking either or offered memory protection or generated a general protection fault if you tried to mask the interrupts. Wink Not even the early AmigaOS did! And it had great preemptive multitasking capabilities, a great GUI, etc.. but no memory protection or virtualization.

I think it would be better to think in terms of definitions: DOS = Disk Operating System. Those times having support for disks was the "BIG" thing, and thus that term was the most predominant. But this has nothing to do neither with multitasking, nor with lack of memory protection, nor with lack of a GUI, nor with anything else than being able to let you load and save files on a floppy or hard disk.

So, the right definition for the XBox OS can only be "a stripped down NT5 Kernel" IMHO, because that's more or less exactly what it is. Wink
Post 15 Nov 2006, 17:03
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rugxulo



Joined: 09 Aug 2005
Posts: 2341
Location: Usono (aka, USA)
rugxulo
BTW, Happy 5th Birthday, XBox! (okay, well, at least in my timezone, heh). I enjoyed playing Sonic Mega Collection Plus today (and still haven't unlocked anything, doh, I'm such a slacker).
Post 16 Nov 2006, 04:02
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Filter



Joined: 08 Oct 2006
Posts: 67
Filter
It's very clearly not a version of DOS. It doesn't seem to be very closely related to NT either. It's probably some variant of NT or is somehow loosely based upon NT technology. I'm very sure they wouldn't bother going back in time to dig up an operating system that most people wish would go away (I'm talking about MS-DOS not FreeDos or others similar).
Post 17 Nov 2006, 03:25
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Dex4u



Joined: 08 Feb 2005
Posts: 1601
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Dex4u
@Filer, I also do not think it users any part of Dos, i think most people are thinking in terms of MSDos, when what i mean is Dos design.

My ? should of been, If Dos was 32bit pmode OS, that ran 100% once booted in pmode, would it be like this ?:
http://www.extremetech.com/article2/0,1697,1670116,00.asp
Post 17 Nov 2006, 16:00
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