A process started with the -D option has some special privileges, which might lead to data destruction if used indiscriminately:
Access to the virtual machine is always granted, even if the Initialization lock is set. In particular, it would be possible to start a user process while line 0 is in the process of initializing the virtual machine. Therefore, always verify that line 0 has reached, at least, the diagnostics stage before starting a process.
When the memory is full, the debugger can abort with the message MEM FULL. Perform a flush and retry until it succeeds.
When the system runs in single-user mode (with a lock set by the command s0+), do not try to shut down the system with the TCL command shutdown. Instead, go to the monitor debugger, use a flush (f) and kill the flush process (kf). This terminates all active processes.
When changing virtual memory with the debugger, it is recommended to flush memory frequently, using the f command.