Start an instance, Mount the Database and Open the Database.
Rolling forward to recover data that has not been recorded in data
files, yet has been recorded in the on-line redo log, including the
contents of rollback segments. Rolling back transactions that have
been explicitly rolled back or have not been committed as indicated by
the rollback segments regenerated in step a. Releasing any resources
(locks) held by transactions in process at the time of the failure.
Resolving any pending distributed transactions undergoing a two-
phase commit at the time of the instance failure.