Backing up using the SQL Server 2005 mirror option (23037)

FQQ's on backup with the mirror option is taken :
1. Does it write one backup and then the other?
2. Does it create one backup and then copy the backup to the mirror location?
3. Is the completion time (as far as data is concerned) the same for both?

When a backup processed with mirroring enabled :

1. Does it write one backup and then the other?
Answer: The destination backup files are written simultaneously.

2. Does it create one backup and then copy the backup to the mirror location?
Answer: It actually does the backup to two locations, there is no copying.

3. Is the end -time (as far as data is concerned) the same for both?
Answer: Yes, however low disk I/O can create differing times.