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 Problems When Running Under DPMI
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     If you have a program that runs well under DOS but abnormally terminates
     when it runs under a DPMI host, such as Windows 3.1 in enhanced mode, or
     a Virtual DOS Machine under OS/2 2.0, check for the following problems:

     .  How much memory does your application require?

        Ensure that enough extended memory is available from the DPMI host.

     .  Does your program shell out to another program?

        In the DPMI 0.9 specification (which enhanced-mode Windows 3.x
        follows), only one protected-mode application can run on a virtual
        machine at a time.  That means that you cannot run two protected-mode
        programs in the same DOS box under Windows 3.1 in enhanced mode.

        Modify your program so that it does not shell to a protected-mode
        program.  DPMI hosts that follow the 1.0 specification allow more
        than one protected-mode application to run.  Some 0.9 DPMI hosts have
        extensions that allow two protected-mode applications to run on the
        same virtual machine, but it is difficult to detect this capability.