If you're experiencing difficulties while running a specific DOS program, you can fine-tune the VDM environment for the particular application, allowing it to run more smoothly, or in some cases simply allowing it to run at all. DOS property settings can affect many aspects of an application's operation, such as (but not limited to) the following:
• The drive and folder (directory) selected as the default when an application starts
• Full-screen or windowed operation upon launch
• Conventional memory usage
• Expanded or extended memory usage
• The application's multitasking priority level ■ The application's shortcut keys
• Foreground and background processing
To edit these properties for a DOS program, do the following:
1. Find the program file or a shortcut to it.
2. Right-click and choose Properties.
If the program is stored on an NTFS-formatted partition, the standard Security tab will also be listed in the Properties dialog box.
Poke through each tab, and use the ? (question mark) button for help on the settings. Educational and game programs will most often require you to adjust the Memory and Compatibility settings.
You can choose to further configure the MS-DOS and Windows 3.x environment by modifying Windows 7's equivalent of the old CONFIG.SYS and AUTOEXEC.BAT files. These files are called config.nt and autoexec.nt and are used to configure each DOS VDM when it starts up. Just remember:
• The files CONFIG.SYS and AUTOEXEC.BAT in your hard drive's root folder are completely ignored by Windows 7. If they're there at all, it's only to fool really old applications that won't run unless they see that these files exist.
The Screen tab's Usage options determine whether the application initially comes up windowed or full screen. You still can toggle between views by pressing Alt+Enter. Of course, in full-screen display, the mouse is surrendered to the application. When you use a mouse with a windowed application, the mouse works within the window on its menus, and with Windows when you move the mouse back to the Windows desktop. No DOS-based mouse driver is needed. Mouse support is provided automatically.
• The files config.nt and autoexec.nt in \windows\sys-
tem32 are used, but only when Windows needs to start up an MS-DOS or Windows 3.x application. Any change to these files will take effect the next time you start the application—you don't need to restart Windows.
The standard settings in config.nt as set up when Windows is installed are shown in the following listing. The REM comments have been removed for brevity. (If you upgraded your computer from an earlier version of Windows, your config.nt file might be different because the installer might have retained some of your previous operating system's settings.)
dos=high, umb device=%SystemRoot%\system32\himem.sys files=40
You can edit the config.nt and autoexec.nt files with a simple text editor such as Notepad. They're protected files, however, so you must run an elevated version of Notepad, using this procedure:
1. Click Start, All Programs, Accessories.
2. Right-click Notepad and select Run As Administrator.
3. Confirm the UAC prompt, or enter an Administrator password as requested. (Alternately, you can just type notepad in an elevated Command Prompt window).
4. Click File, Open, and browse to \windows\system32. Select autoexec.nt or config.nt as desired.
On my computers, I always change the files setting to files=100 and add the line device=%SystemRoot%\ system32\ansi.sys.
For more information about ansi.sys, see the next section.
The MS-DOS Environment
Was this article helpful?