Disabling the DOS Redirector with Pervasive.SQL
Last Updated: 10/20/2005


Older Btrieve for DOS applications use a simple interface -- a software interrupt 0x7B -- to access the database. When you install Pervasive.SQL 2000i or newer into an environment that is currently running an old DOS application like this, you will likely run into problems. This paper explains how to resolve the issue.

1. Use the New Pervasive.SQL Engine
By far the best solution is to configure your old DOS application to use the new engine. In most cases, this is as simple as moving the application and all of its corresponding database files to the new server (the one with Pervasive.SQL installed). You may need to make some configuration changes on the application to indicate the new drive letter or server name -- check with your vendor for detailed information on that aspect of the move.

Once you have moved all the data, the rest is easy. If you have Windows NT/2000/2003/XP, simply run the old application from within a DOS window. There is no need to run BTRIEVE.EXE or BREQUEST.EXE at all. The built-in DOSBOX redirector will handle getting the DOS calls out through the Win32 interface to the engine -- and everything works from there! If you have Windows 95/98/ME machines, you will need to manually load the BTRBOX95.EXE application before starting your application. This will put a blue icon on the system tray. Then, inside the DOS box (before you run the application), run BDOSSTUB.EXE. Again, you will NOT need to run BTRIEVE.EXE or BREQUEST.EXE in this configuration.

If the application launches with batch files, you can detect the current OS and perform the needed steps within the batch file, at the same point where the BTREIEVE or BREQUEST command lines were. You will NOT need to use the BUTIL -STOP command or BREQUTIL /U: command at the end of the script.

2. Disable the DOS Redirector
If you would rather not mix the engines or applications, and if the newer application has *NO* DOS components at all, then you can disable the DOS redirector. To do this on Windows NT/2000/2003/XP, find the file C:\WINDOWS\SYSTEM32\CONFIG.NT or C:\WINNT\SYSTEM32\CONFIG.NT and remove (or comment out) the line containing BTRDRVR.SYS. To do this on Windows 95/98/ME, search the registry for "BTRBOX95.VXD" and remove any registry keys that you find containing it. Now, your old DOS applications will run just like before.

Pervasive's :Support Tool" may be able to perform these changes for you automatically, if you wish to try it.

3. Separate the Applications
If the above solutions are not possible, then the third option is to completely segregate the applications. Simply do not install the Pervasive.SQL client onto systems that must run the older application. This may mean that some users will need two computers, or that you may need to invest in virtual computer technology, but it is the only sure way to keep the applications apart.

Of course, if you still can't get it to work, contact Goldstar Software and let us work with you to help!