IsDBL 1.3 Is the specified drive a virtual DBLSPACE volume?

  IsDBL C:
  If Errorlevel 2 GoTo SyntaxError
  If ErrorLevel 1 GoTo IsDBLDrive
  GoTo IsOrdinaryDrive

In debugging you might just use to view the errorlevel result.

echo %ERRORLEVEL

Copyrighted but may be freely distributed and used for any
purpose except military. Based on a program of the same name
written by Dan Wright. Version 1.3 just embeds the new
address and phone number. This utility is of use only to old DOS and
Windows 3.1 machines.