Monitor Debugger

The monitor debugger is a tool used for recovery in the case a system failure or access to system resources are unavailable by the virtual debugger.

The monitor debugger allows:

  • displaying and changing D3 virtual memory.

  • displaying and changing real memory (UNIX virtual memory).

  • forcing a flush of the D3 memory space back to disk.

  • displaying and changing the status of the system semaphores to remove a dead lock situation.

  • accessing a locked system.

  • terminating processes and shut down.

  • tracing modifications to a memory area.

  • putting low level breakpoints in the virtual code.

When the monitor debugger is entered unexpectedly, first type g, and then press ENTER to restart the system. If the system does not restart, press BREAK to examine the problem. There are cases when the debugger is entered incorrectly. For example, when long, unbreakable, tape operations (for example, a rewind) are running, pressing BREAK several times on line 0 may enter the monitor debugger with a tight loop condition. This means that the process was engaged in a long operation, preventing it from servicing the BREAK key.