IsMSDOS()

         Determines if Operation System is MSDOS or DRDOS

    Syntax:

         IsMSDOS() -> lIsMSDOS

    Description:

         Determines if Operation System (OS) is a Microsoft DOS (MSDOS) or
         a Digital Research DOS (DRDOS).

    Return:

         .F. for DRDOS and .T. for MSDOS (or another one).

    Example:

         If IsMSDOS()
           Warning ( "Very good Bill G..." )
         EndIf