Frequently Asked Questions  -  1. Getting started
Before a new version of vDos is released, vDosSetup (and vDos itself) is submitted to and tested using several (at this moment 61) anti-virus programs. Eventual false positives are then reported (submitting vDosSetup) to those anti-virus companies.
But it seems an anti-virus program could still later on mistrust the same vDosSetup it once approved of; Windows Defender (once/twice ?) did.
If your anti-virus program complains about vDosSetup; first make sure your anti-virus program (its virus database) is up-to-date. Eventually go to, and check vDosSetup ( for yourself.
When you run the downloaded vDosSetup installation program, it will offer to create a vDos folder on your C: drive. You can select another location, but C:\vDos is a good starting point for a first-time impression and testing.
vDosSetup doesn’t modify anything to your Windows system. It only creates that vDos folder, a start menu entry and a shortcut on the desktop. There’s even no uninstall option. If vDos doesn't work for you, you'll have to delete those mentioned items by hand!
The vDos folder will contain these files:
  • 4DOS.HLP
    The help text for the vDos/4DOS command line interpreter.
  • autoexec.txt
    The equivalent of DOS autoexec.bat.
  • config.txt
    DOS had config.sys, Windows config.nt, vDos config.txt. Like autoexec.txt, the .txt extension is for easy modifications, without Windows trying to ‘execute’ something.
  • Getting Started.pdf
    An introduction to vDos, please read this.
  • Printing.pdf
    Documentation on vDos’ printing capabilities. To be read once you come to printing from your DOS application(s).
  • vDos.exe
    The program that will emulate a DOS PC to run your applications.

And two subfolders:
  • 4DOS
    Some 4DOS specific utilities. If you’re not into (enhanced) batch processing, you can just delete this folder.
    The DataPerfect TestDrive demo program, started by the initial autoexec.txt file. Once you ran it to confirm vDos will work on your Windows, you can of course delete this folder.
Start vDos by either the desktop shortcut, or the vDos start menu.
The vDos window should appear, waiting for a keystroke to start the DataPerfect Testdrive demo DOS program.
Once your application ran in DOS, then it was migrated to Windows 32-bit.
Now you’re facing vDos, it is ‘merely’ a Windows program that should enable you to run that DOS application (with additional features) in for instance Windows 64-bit

For now, we’re in a testing phase, and assume vDos is installed to the default Windows C:\vDos folder.
  • Open the vDos autoexec.txt file, and just delete all its contents; the demo program doesn't need to start anymore. Save the empty file, and start vDos again.
  • That will bring the famous C:\> DOS prompt. Notice however that vDos C: isn’t Windows C:! Instead the vDos C: at this moment defaults to the Windows C:\vDos folder. Eventually do a DIR command to see the files and folders on this vDos C: drive. Leave the vDos window open.
  • You will still have your application running on some system. Copy its folder(s) to the vDos folder. So you’ll have something like C:\vDos\DosApp, C:\vDos\DosData…
  • Have a close look at how the application was started before. That would be by some batch file, we’ll assume it is “start.bat”. If it isn’t already in the copied folder(s), copy that also to the C:\vDos folder.
  • Do another DIR command in the vDos window, you’ll see the newly copied folder(s). Now start the application by start.bat (it’s in vDos C:), or folder\start.bat (substituting folder by the name start.bat is located in). If the application starts, you end it and get back to the DOS prompt; Close the vDos window by issueing EXIT.
  • If the application doesn’t start, that will most likely be because it expects (relies) on a drive letter or directory structure that doesn’t match what we got so far in vDos. If it for instance expects a F: drive letter with the program and data files (DosApp, DosData…), you’ll have to assign the vDos F: to the correct Windows folder. That would be C:\vDos in this example. Issue USE F: C:\vDos, then select that drive by F:, so you’ll get a F:\> DOS prompt. Now try to start the application again. If it still doesn’t start, open the batch file that starts the application in for instance Notepad (don’t double click the batch file!). Look for the line that starts your application. If some other program is started before that, temporary disable that/those by adding REM. For instance REM program, save the batch file, and try again.
  • If you still have troubles starting the application, post your problem at the vDos forum. Specify what vDos version you’re using (should be the most recent), what directory structure you have (C:\vDos\DosApp…), what application you try to start, and how it is supposed to start (the start.bat contents).
  • Open autoexec.txt, if you didn’t already delete its contents, do it now.
  • Add the command lines that you entered by hand in the previous section.
  • For instance:
    USE F: C:\
    CALL DosApp\
  • Save the file, and start vDos again.
  • Issue EXIT to close the vDos window.
  • If your application doesn’t start, correct the command lines in autoexec.txt.
  • Add a last command line to autoexec.txt: EXIT, so the vDos window will close automatically the moment you end the application.
We assumed you copied the application folder(s) temporary to Windows C:\vDos. And the application was started by autoexec.txt with:
USE F: C:\vDos\
CALL DosApp\start.bat

To start the application with the ‘live’ data, change the folder reference in the first line to where the DosApp is actually located. For instance:
USE F: \\server\share\
That’s it.
If you have more than one DOS application:
  • Copy config.txt and autoexec.txt to a separate folder, preferably nearby the second application.
  • Modify autoexec.txt so that application is started. Eventually temporary rem-out the last EXIT and test.
  • Create a new (desktop) shortcut to vDos.exe, or just copy the installed one.
  • Give it a sensible name, like “DOS accounting”. That will also be displayed in the title bar of a framed vDos window.
  • Go to the properties of the shortcut (right click), set the Start in: property to the folder containing the autoexec.txt and config.txt of  that second application.
  • Eventually, if you like to; assign a Shortcut key, or some other Icon to the shortcut.