(Free)DOS subsystem

[Imre Leber]

Hi,

I guess i am new to this list.

I have been a maintainer on the FreeDOS project for more then 7 years.

I have also noticed that you are still looking into building a DOS subsystem in reactos.

After the release of FreeDOS version 1, I would like to see wether I could not take up the task to having it running under reactos.

My main idea involves using a port of DOSemu.

Is there any documentation regarding the running of a DOS subsystem in windows that I should study beforehand?

Imre

[James Tabor]

Imre Leber wrote:
> Hi,
>
> I guess i am new to this list.
>
> I have been a maintainer on the FreeDOS project for more then 7 years.
>
> I have also noticed that you are still looking into building a DOS subsystem in reactos.
>
> After the release of FreeDOS version 1, I would like to see wether I could not take up the task to having it running under reactos.
>
> My main idea involves using a port of DOSemu.
>
> Is there any documentation regarding the running of a DOS subsystem in windows that I should study beforehand?
>
> Imre

Hi Imre!
Welcome to ReactOS! 8^D

The idea is still open.

We've tested Qemu under ReactOS running FreeDOS at one time and it does work. Another project that 
was tested, DOSBox, it works like DOSemu, http://dosbox.sourceforge.net/

Running a dos-subsystem and docs? Maybe one of the other developers can help here. You can look at 
the OS2 subsystem at http://svn.reactos.ru/svn/reactos/trunk/os2/ , it's incomplete, this would be 
your best starting point. There is allot more to it. You need to dive into the code and start 
reading. I do not recall any docs or books dealing with rolling your own subsystem. The best book
you can get for understanding Windows or ReactOS is, Windows Internals. Understanding the Csrss 
subsystem would help with the os2 one.

Anyway, some projects that could be good examples on how to do this, Posix subsystem, 
http://sourceforge.net/projects/winntposix ,and running linux bins in windows, 
http://sourceforge.net/projects/keow . One of our developers is currently working with CoLinux, 
http://www.colinux.org/ .

Sorry I couldn't help you more here.

Thanks,
James

[Myria]

I've wanted to write an NTVDM for ReactOS, but I'm not sure when I'd ever 
have time.

Windows NT's DOS subsystem, NTVDM, is a user-mode program that runs on top 
of Win32.  It runs DOS programs as Windows processes, using v86 mode to run 
the programs.  DPMI programs are supported by asking the kernel to allocate 
LDT segments and running directly.  (If you write a DOS32 program and know 
the correct addresses, you can call MessageBoxW in user32.dll and it will 
work.)

This differs significantly from DOSBox, which is effectively a machine 
emulator rather than an API translator.  DOSEmu, in comparison, is 
essentially the same design as NTVDM but for Linux.

FreeDOS in DOSBox works very well, because the FreeDOS kernel is its normal 
self and is unaware that it's inside a VM.  However, this doesn't work for 
NTVDM/DOSEmu.  In these, the FreeDOS kernel will need to be heavily 
modified, particularly because the NT kernel handles file I/O.  Programs 
inside the virtual DOS environment use illegal opcodes to talk to NTVDM.

Melissa

----- Original Message ----- 
From: "James Tabor" [e-mail]
To: "ReactOS Development List" [e-mail]
Sent: Monday, August 28, 2006 14:19
Subject: Re: [ros-dev] (Free)DOS subsystem
> Imre Leber wrote:
> > Hi,
> >
> > I guess i am new to this list.
> >
> > I have been a maintainer on the FreeDOS project for more then 7 years.
> >
> > I have also noticed that you are still looking into building a DOS 
> > subsystem in reactos.
> >
> > After the release of FreeDOS version 1, I would like to see wether I 
> > could not take up the task to having it running under reactos.
> >
> > My main idea involves using a port of DOSemu.
> >
> > Is there any documentation regarding the running of a DOS subsystem in 
> > windows that I should study beforehand?
> >
> > Imre
>
> Hi Imre!
> Welcome to ReactOS! 8^D
>
> The idea is still open.
>
> We've tested Qemu under ReactOS running FreeDOS at one time and it does 
> work. Another project that
> was tested, DOSBox, it works like DOSemu, http://dosbox.sourceforge.net/
>
> Running a dos-subsystem and docs? Maybe one of the other developers can 
> help here. You can look at
> the OS2 subsystem at http://svn.reactos.ru/svn/reactos/trunk/os2/ , it's 
> incomplete, this would be
> your best starting point. There is allot more to it. You need to dive into 
> the code and start
> reading. I do not recall any docs or books dealing with rolling your own 
> subsystem. The best book
> you can get for understanding Windows or ReactOS is, Windows Internals. 
> Understanding the Csrss
> subsystem would help with the os2 one.
>
> Anyway, some projects that could be good examples on how to do this, Posix 
> subsystem,
> http://sourceforge.net/projects/winntposix ,and running linux bins in 
> windows,
> http://sourceforge.net/projects/keow . One of our developers is currently 
> working with CoLinux,
> http://www.colinux.org/ .
>
> Sorry I couldn't help you more here.
>
> Thanks,
> James
>
> Ros-dev mailing list
> [e-mail]
> http://www.reactos.org/mailman/listinfo/ros-dev

[Peter Dolding]

Myria wrote:
> I've wanted to write an NTVDM for ReactOS, but I'm not sure when I'd ever 
> have time.
>
> Windows NT's DOS subsystem, NTVDM, is a user-mode program that runs on top 
> of Win32.  It runs DOS programs as Windows processes, using v86 mode to run 
> the programs.  DPMI programs are supported by asking the kernel to allocate 
> LDT segments and running directly.  (If you write a DOS32 program and know 
> the correct addresses, you can call MessageBoxW in user32.dll and it will 
> work.)
>
> This differs significantly from DOSBox, which is effectively a machine 
> emulator rather than an API translator.  DOSEmu, in comparison, is 
> essentially the same design as NTVDM but for Linux.
>
> FreeDOS in DOSBox works very well, because the FreeDOS kernel is its normal 
> self and is unaware that it's inside a VM.  However, this doesn't work for 
> NTVDM/DOSEmu.  In these, the FreeDOS kernel will need to be heavily 
> modified, particularly because the NT kernel handles file I/O.  Programs 
> inside the virtual DOS environment use illegal opcodes to talk to NTVDM.
>
> Melissa

True  Closest Freedos to Windows NT NTVDM is 
http://freedos-32.sourceforge.net/.   Its was newer version under 
development.  It could be stalled from 2005.

Peter Dolding

[Sylvain Petreolle]

--- Peter Dolding [e-mail] a écrit :
> >
>
> True  Closest Freedos to Windows NT NTVDM is 
> http://freedos-32.sourceforge.net/.   Its was newer version under 
> development.  It could be stalled from 2005.

Its still active, but they dont release very often.
(they even have a windows module)
working good afaict.

Kind regards,
Sylvain Petreolle (aka Usurp)
--- --- --- --- --- --- --- --- --- --- --- --- ---

Run your favorite Windows apps with free ReactOS : http://www.reactos.org
Listen to non-DRMised Music: http://www.jamendo.com

Linux is not as well stable as it is told to. The proof is, mine has restarted two years ago, on the occasion of a power cut.
- H. Eychenne

[Aleksey Bragin]

Hello Imre,
it's very nice to see you on this mailing list!

A proper, Windows-compatible DOS subsystem would be implementing a  
NTVDM thing, however it's not a very trivial thing to do (I wish  
Myria has time to do it somewhen :-) ).

But we thought a lot about using dosbox/qemu/dosemu with a freedos  
installed in order to give a virtual machine running DOS (FreeDOS)  
for users. The problem exists though how to access hardware (like  
harddisks for example)...

I'm interested in your idea, and if you need any help with reactos -  
please feel free to post here.

With the best regards,
Aleksey Bragin
ReactOS Project Coordinator

On Aug 28, 2006, at 10:48 PM, Imre Leber wrote:
> Hi,
>
> I guess i am new to this list.
>
> I have been a maintainer on the FreeDOS project for more then 7 years.
>
> I have also noticed that you are still looking into building a DOS  
> subsystem in reactos.
>
> After the release of FreeDOS version 1, I would like to see wether  
> I could not take up the task to having it running under reactos.
>
> My main idea involves using a port of DOSemu.
>
> Is there any documentation regarding the running of a DOS subsystem  
> in windows that I should study beforehand?
>
> Imre