[ros-general] Academic research about ReactOS

[Timo Kreuzer]

Hi Luis,

Sorry for the late answer, I had hoped someone else would step in 
(*looks at Aleksey*), but probably everyone thought like that :)

Since the ReactOS kernel is in many parts architecturally close to 
Windows 2003, so the best documentation about ReactOS kernel 
architecture is Windows Internals 4.
* Both Process Management and I/O management work the same as in 
Windows, there are no known architectural differences. We use the data 
structures from Windows 2003 symbol files to provide maximum driver 
compatibility. Windows Internals 4 will describe it quite perfectly.
* Memory Manager: This is one of the parts that is partly different from 
Windows architecture. The original design was quite different from 
Windows and proved to be problematic. Alex rewrote several parts of it 
to be much more like in Windows, while other parts still rely on old 
mechanisms. For example we currently use 2 meachnisms for virtual 
address management: VADs (this is what Windows uses) and "Memory Areas", 
a reactos custom mechanism, still used for file sections. These 2 are 
glued together with some hacks. Basically all code in the "mm/ARM" 
folder is the code that has been reworked to be close to Windows 
architecture, while the code in the "mm" folder is older code, which has 
many differences from Windows.
* Related: the Cache Manager, which has been undergone a major rewrite, 
but only parts of that rewrite are in use, other parts still live in a 
branch, and Arty, the author currently has almost no spare time to 
finish it. I cannot say how close it is to Windows, you need to ask Arty 
about that.
* File systems: ReactOS currently uses FAT/FAT32. The driver is an IFS 
driver and should probably work on Windows, too.  In fact we have 2 
drivers: fastfat and fastfat_new, but the latter is not ready for prime 
time yet, iirc. Aleksey might tell you more about that. We also have an 
NTFS driver in our sources based on the linux NTFS-3G, but afaik it's in 
an poor state and doesn't work. We have an ext2/3 driver, which almost 
works, but requires code from the Cache Manager rewrite. The ext driver 
is a 3rd party module, which was developed for Windows. And we have 
cdfs. Basically all FS drivers are designed to be Windows IFS drivers

If you want to know more, just ask, either here or in our #reactos-dev 
irc channel on freenode (ask a mod for "write access"). Hopefully next 
time it will not take as long...

Good luck with your presentation.
Timo


Am 04.04.2013 23:15, schrieb Luis Andrade Neto:
> Hi,
>
> My name's Luis, I'm from Brazil and I've been interested in ReactOS for a few years (though not actively participating in the project). This semester, I'm having Operating Systems subject in my university (I'm doing a major in Computer Science), and I've chosen to make a presentation about ReactOS.
>
> Where can I get documentation about the following parts of the ReactOS system, and, most importantly, its differences to MS Windows?
>
> * Process management (e.g. scaling algorithms)
> * Memory management
> * File systems (it uses FAT, right? But are there any differences to MS Windows)
> * I/O device management
>
> BTW, sorry for my poor English and writing skills. :)
>
> Thanks in advance and kindest regards,
>
> Luis Andrade
>
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