How does the system cope up with a record crash when recovery is going on after the first crash?
Ans: In a system the undo and redo operations are needed to be idempotent to cope up with a record crash while recovery is going on after the crash. Because of the idempotent property, recovery process, whereas in the process of undoing or redoing the actions of a transaction, may fail without a trace, and this kind of failure can take place any number of times before the recovery is done successfully.