Basics
Oracle DB : A set of physical files on disk that continues to exist even if the m/c is down.
Oracle instance : Processes and shared memory areas that access the DB. Both usually have same name.
Offline (‘cold’) backup dos not need the instance (uses OS facilities to backup entire files).
Startup phase : Starts the instance using initialization parameters to configure the instance. Processes and shared memory area are created in this phase. Parameters : DB name, area sizes (DB block size, buffer size, sort area), etc.