⟩ From where does PMON gets the conformance about failure? How is the user process terminated?
When user process is terminated abruptly due to power cut or any other factors then oracle database instance goes down then PMON mandatory background process is activated i.e it will then writes the commited data into respective datafiles which we can call this process as rollforward. if the data is not commited then by the action of rollbackword it erases the data from datafiles.