Overlay component instrumentation can be difficult to debug because of its transitory nature. To facilitate this kind of debugging, you can use a debug option when running the service layer on Windows NT. Refer to the SystemView Agent for Win32 User's Guide for information on how to stop the service layer.

Because the service layer normally runs as a background process, you must stop the service layer (if it's already running) before you use this option.

To start the service layer with the debug option, enter the following command from a DOS command prompt:

START DMISLSRV DEBUG

If the subdirectory containing the service layer executable file is not in your PATH statement, enter the appropriate drive and path as part of the command.

When the service layer is loaded, a debug address is displayed. When you set a breakpoint at this address, execution stops just before the DmiCiInvoke() function call is issued. At this point the overlay component DLL is already loaded, and you can specify breakpoints in the instrumentation wherever you need them.

You can display the version of the service layer on Windows NT by issuing the following from a DOS command prompt:

DMISLSRV VERSION

This displays version information without starting the service layer. You can issue this command while the service layer is running.